Thrombectomy and soft debris removal device

ABSTRACT

A device suitable for removing material from a living being is provided, featuring at least an aspiration pump, powered by a motor. The aspiration pump and any optional infusate pump preferably feature a helical pumping mechanism, and operate at a high rate of rotation, thereby ensuring adequate pumping performance and flexibility. The helical pumping mechanism may be a helical coiled wire about a central core tube. The helical coil wire, whether together with, or independent of, the core tube, may be rotated to cause a pumping action. Additionally, a narrow crossing profile is maintained, ensuring that the device may reach more tortuous regions of the vasculature. In one embodiment, the system comprises a wire-guided mono-rail catheter with a working head mounted on a flexible portion of the catheter that can laterally displace away from the guide wire to facilitate thrombus removal. The working head may be operated to separate and move away from the guide wire to come within a closer proximity of the obstructive material to more effectively remove it from the vessel.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a Continuation of U.S. patent applicationSer. No. 11/871,908, filed Oct. 12, 2007 and entitled, “Thrombectomy andSoft Debris Removal Device”, which is a Continuation-in-Part of U.S.patent application Ser. No. 11/751,443, filed May 21, 2007 and entitled,“Thrombectomy and Soft Debris Removal Device”, which is aContinuation-in-Part of U.S. patent application Ser. No. 10/832,830,filed Apr. 27, 2004 and entitled, “Thrombectomy and Soft Debris RemovalDevice”. The entire contents of these prior applications are expresslyincorporated by reference for all purposes.

BACKGROUND OF THE INVENTION

This application relates generally to medical instruments and methods ofuse to remove occlusive material from a vessel, duct or lumen within thebody of a living being, specifically relating to the removal of thrombusor soft tissue clots from vascular or other lumens. A preferredembodiment more particularly concerns a device useful for clearinglumens relying on a device, incorporating at least one pumping means, toaspirate the debris, thereby clearing a partial or complete blockage ofthe vessel or lumen.

Vascular disease affects a large population each year. Indications ofvascular disease include blood clots in the vascular system, possiblyresulting in deep venous thrombosis (DVT), embolisms or ischemia. Theclots are formed by aggregations of thrombus and fibrin, resulting inpartial or total occlusion of the vessel. Various approaches totreatment may be performed, including treatment with lysing agents tochemically disperse the occlusion, or mechanical restoration of patencyto the vessel may be attempted, such as Catheter Directed ThrombolyticTherapy.

Mechanical thrombectomy devices may be used to restore patency to avessel that had been at least partially occluded by material. Forexample, rotary catheters may employ a rotary cutting head, a rotatingmacerator or some homogenization device to remove the clot by theeffects of a hydrodynamic vortex generated near the clot. Alternatively,some instruments repeatedly drum into the occlusive material, displacingand distorting the material in order to create a lumen therethrough,while leaving the material within the vessel. Arguably, for the longterm benefit of the patient, it is desirable to effectuate the removalof the occlusive material, yet care must be taken to ensure that loosedebris, such as fragments of thrombus, are unable to travel away fromthe site to cause a life threatening injury such as an embolism, strokeor heart attack.

Helical pump designs have been incorporated into medical devices, forexample, Hatamura et al. in U.S. Pat. No. 6,554,799 describes utilizinghigh-speed rotation of a fixed twin filament rotor for transferringliquids in an inflexible needle. Any leakage of fluid through theclearance between the rotors and the surrounding needle is minimized bythe viscosity of the liquid in combination with high-speed rotation ofthe rotor.

Catheter instruments have been suggested or disclosed in the patentliterature for effecting non-invasive or minimally invasiverevascularization of occluded arteries. For example, in U.S. Pat. No.4,445,509 granted to Auth, there is disclosed a recanalization catheterdesigned specifically for cutting away hard, abnormal deposits, such asatherosclerotic plaque, from the inside of an artery, while supposedlypreserving the soft arterial tissue. That recanalizing catheter includesa sharp-edged, multi-fluted, rotating cutting tip mounted at the distalend of the catheter and arranged to be rotated by a flexible drive shaftextending down the center of the catheter. The rotation of the cuttinghead is stated as producing a “differential cutting” effect, whereuponthe rotating blade creates a cutting action that removes the relativelyhard deposits and selectively leaves the relatively soft tissue. Suctionports are provided to pull the hard particles produced by the cuttingaction into the catheter for removal at the proximal end thereof so thatsuch particles do not flow distally of the catheter where they couldhave an adverse effect on the patients' body, as previously discussed.

Additional rotating burr designs have been described, for example, foruse in clearing asymmetrical plaque build-up within a vessel. Shturmanin U.S. Pat. No. 5,312,427 provides lateral directional control to anatherectomy device by deploying an exposed rotating burr, in such a waythat it can be extended laterally away from a guidewire in a single axisand directed by a positioning wire having a pre-determined shape. Inthis manner, the rotating burr can be directed into the asymmetricalplaque lesion, and thereby prevent normal vascular tissue (not coveredwith plaque) from damage due to contact with the high-speed rotation ofthe exposed burr. Shturman et al. in U.S. Pat. No. 6,494,890, alsodescribe a rotational atherectomy device having a rotating driveshaftwith an eccentric enlarged diameter section having an abrasive surfacefor removing tissue. By the nature of the eccentric rotation, a largerdiameter than the outer diameter of the enlarged section may be clearedfrom stenotic tissue.

Also granted to Auth, U.S. Pat. No. 5,695,507, describes a helicallywound coil wire, entrained within a catheter, that may be used to cleara thrombus blocked-vessel by causing the insoluble fibrous meshedstrands of fibrin to wrap themselves around the helical wire. As thedrive cable and associated helical wire rotate, the fibrin of thethrombus material may be drawn to a port by suction applied at theproximal end, thereby engaging the fibrin with the rotating, wrappingaction of the helical coil wire. Alternatively, without applying anyvacuum, the fibrin may become wrapped around the wire by the frictionbetween the wire and the thrombus or the “whirling” effect of therapidly rotating wire. Furthermore, drug delivery may be accomplishedthrough the same fluid path in the housing in which the coil wire iscontained.

In U.S. Pat. No. 4,700,705, which is assigned to the same assignee asthis invention and whose disclosure is incorporated by reference herein,there are disclosed and claimed catheters and methods of use foreffecting the opening of a vessel, duct or lumen, such as the opening ofa atherosclerotic restriction (partial or total occlusion) in an artery.These catheters are elongated flexible members of sufficient flexibilityto enable them to be readily passed through the body of the patient tothe situs of the atherosclerotic plaque in the artery to be opened. Aworking head is mounted at the distal end of the catheter and isarranged for high-speed rotation about the longitudinal axis of thecatheter. In some embodiments the catheter may eject fluid at theworking head to expedite the restriction-opening procedure.

In U.S. Pat. No. 4,747,821, which is also assigned to the same assigneeas this invention and whose disclosure is incorporated by referenceherein, there is disclosed and claimed other catheters particularlysuited for revascularization of arteries. Each of those cathetersincludes a rotary working head having at least one non-sharp impactingsurface to effect material removal without cutting. Moreover, thosecatheters are arranged to eject fluid adjacent the working head toexpedite the revascularization procedure. In particular, the rotation ofthe working head produces a powerful, toroidal shaped vortex contiguous,or adjacent, with the working head, which has the effect ofrecirculating any particles that may have been broken off from thematerial forming the arterial restriction so that the working headrepeatedly impacts those particles to reduce their size.

Other atherectomy devices for enlarging an opening in a blood vesselhave been disclosed and claimed in the following U.S. Pat. Nos.4,589,412; 4,631,052; 4,686,982; 4,749,376; 4,790,813; and 6,080,170(which is assigned to the same assignee as this invention and whosedisclosure is incorporated by reference herein).

In U.S. Pat. No. 5,074,841 granted to Ademovic et al., there isdisclosed a catheter device for performing an atherectomy. The devicefeatures an exposed series of slots in an outer housing, with a helicalcutting blade rotating therein. The helical cutting blade, inconjunction with the slots, serves to sever the material and the rotarymotion draws the fragments towards a grinding face of a ferrule. Theground particulate material may then be directed into a pair of flushinglumens, and aided by saline delivered to the site through saline lumens,flushed away from the treatment site.

In U.S. Pat. No. 4,857,046 granted to Stevens et al., there is discloseda catheter for removing deposits from the inner walls of a blood vesselto increase blood flow through the vessel. The '046 patent discloses aflexible catheter, having a center portion with helical pumping meanswithin a catheter sheath, and having an enlarged distal tip for abradingthe deposits off an inner wall of the vessel, the pumping means andabrading action of the distal tip driven by a proximal drive means.

In U.S. Pat. No. 5,078,722, granted to Stevens, there is disclosed acatheter for removing deposits from the inner wall of a vessel, withouthaving an enlarged distal working head. The '722 patent features arotatable and axially moveable cutting member at the distal end of thecatheter which separates the deposits from the vessel wall by actuationof a circular cutting edge. The rotation of the cutting mechanism isdriven by a tubular transmission, which has a helical wire spiralingabout the exterior, forming a helical pumping mechanism within thecatheter to remove the debris. As the debris accumulates within thecatheter, the inner core member is removable to allow for cleaning, andsubsequent replacement within the outer catheter. The axial movement androtation of the cutting member is controlled by the attending physicianmanipulating an axially slidable and rotatable hardware at the proximalend of the tubular transmission to drive the cutting mechanism,alternatively, the rotary inner core may be energized by incorporationof an electric motor. The distal end of the catheter features aninflatable balloon, whose inflation causes the portion of the catheteropposite the balloon to be pushed into engagement with the inner walllining of the vessel.

U.S. Pat. No. 5,876,414 granted to Straub, discloses a rotary catheterfor clearing a vessel, incorporating a rotor, and optionally a stator,cutting mechanism to sever the material from the vessel wall. As therotor rotates, dual cutting slots engage and sever the material.Furthermore, Straub discloses using a helical pumping mechanism toremove the debris generated by the cutting. The helical pumpingmechanism being a helical coil wrapped around the torque transmittingwire, such that as the rotor is turned, the coiled wire serves as ascrew pump to convey the debris proximally.

U.S. Pat. No. 4,728,319 granted to Masch discloses a catheter forcutting into a blockage in a vessel, the catheter having a sphericalcutting head on the distal end to cut the blockage into fragments. Thecatheter further features a means to deliver an oxygenated infusate tothe cutting mechanism in order to flush the debris away from the cuttingmechanism and clear the cutting means. The catheter system features adrain passage through which vacuum is drawn, so that fragment-ladenfluid is drained through the catheter. Masch further describes that inaddition to, or in lieu of the vacuum application, a helical pumpingmechanism may be used to convey the debris proximally, and away from thetreatment site. In an embodiment employing a helical pump, theinteractions between opposite handed spirals on the adjoining surfacesof the inner and outer tubes cause a pumping action.

U.S. Pat. No. 6,454,775 granted to Demarais et al., discloses a catheterfor clearing a blocked vessel, having a rotatable wire macerator, suchas an expandable wire basket, exposed at the distal end of the catheterto engage and fragment the thrombus within the blocked vessel as therotation occurs. Preferably, the catheter device may incorporate ahelical rotor in order to pump material proximally away from themacerator and the blockage site.

U.S. Pat. No. 6,702,830 is a continuation-in-part of Demarais et al.'s'775 patent, describing an over the wire material transport cathetercapable of infusion and aspiration through the use of helical coiledwires rotating within a lumen to create an Archimedes screw pump. Thescrew pump impeller described by Demarais et al. features an inner tubeor member, and a coiled wire rotor. In one embodiment, there isdescribed a bi-directional catheter featuring a single lumen having awire wrapped around the length of the lumen, coiled in one direction;and further having a second coiled wire inside the length of the lumen,coiled in the other direction. In this manner, rotation of the lumenwill result in infusion and aspiration concurrently. In anotherembodiment, the catheter lumen may house separate, side-by-side lumensfor an aspiration coiled pump and an infusion coiled pump. The pumpimpellers are inserted and run concurrently through the body and mayterminate at spaced-apart ports along the catheter body in order toensure the delivered agents receive adequate residence time within theblood vessel.

U.S. Pat. No. 6,238,405 granted to Findlay, discloses a catheter devicefor removing material having a rotatable screw thread distal endadjacent a shearing member also near the distal end, in order tofragment the clot material. The thrombus is drawn into the device inorder to be macerated, by application of the “Archimedes” screw actionat the distal end, in combination with applied vacuum at the proximalend of the device in fluid communication with the distal end. Theshearing member serves to fragment the thrombus into a manageableparticle size to prevent the device from clogging as the material ispulled the length of the catheter out of the body.

U.S. Pat. No. 5,261,877 granted to Fine et al., discloses a mechanicalthrombectomy device having a high speed canalizing working head, whichrotates to homogenize and facilitate removal of the thrombus, where thedevice is capable of delivering a fluid media into the lumen. The devicefeatures a helical coil wire serving as a bearing to enable thehigh-speed rotation of the distal tip, without the drive cable wearingthrough the guide catheter due to friction. The spiral drive cable isdesigned to be removed to facilitate introduction of infusate liquidthrough the now unobstructed central lumen.

U.S. Pat. No. 6,117,149 granted to Sorenson et al., discloses a deviceto remove ophthalmic lens material in a mammalian eye, having a workinghead at the distal end, driven by a drive shaft having a spiral bearingcoil wire within a rigid sleeve. This device may preferably incorporateseparate passageways for infusion of infusate liquid and aspiration ofmaterial. The patent describes the spiral gap between the individualconvolutions of the helical wire serving as the infusate pathway, whenpressure is applied to a supply reservoir.

U.S. Pat. No. 4,979,939 granted to Shiber, discloses an artherectomysystem for removing an obstruction from a patient's vessel. Shiberdescribes a device having a rotatable coring catheter, which followsalong and around a flexible guidewire. The rotatable coring catheter isconstructed of coiled windings of shaped ribbon, such that in crosssection ridges or steps are incorporated in by the windings, creating aspiral step or ridge. Furthermore the coring catheter features asharpened edge at the end, in order to slice off material from thevessel wall. The guidewire is described as a single pilot wire havingthree helical coil wires wrapped around the length of the pilot wire.Furthermore, the pilot guidewire may be in the form of a hollow tube, inorder to allow delivery of contrast medium or other fluid. In use, therotation of the coring catheter causes the coring end to slice into theocclusive material, and the ridges or steps within the coring catheter,coupled with an aspirating force applied at the distal end of thecatheter cause the material to be moved proximally away from the sitewithin the body. The helical coil wires serve to counter the distalmovement of the obstructing material while being cored, to restrain thecored material from freely rotating around the pilot wire, and to serveas a helical bearing. The helical wires surround the pilot wire are notdriven by the rotation, only the outer catheter is rotatably driven. Thematerial is drawn proximally into the rotating coring catheter, and isremoved along with the catheter itself.

In U.S. Pat. No. 6,156,046, granted to Passafaro et al., there isdisclosed a device for removal of occlusions in a lumen, having aremoval means at the distal end of a torquing member, driven by ahandheld controller. The device utilizes a specially shaped guidewirehaving a guide section serving to orient the cutting head in order toclear a sufficiently large passageway through the lumen. In oneembodiment, the removal means features exposed cutting surfaces thatrotate, causing the removal of material from the vessel wall. Passafarodescribes that the torquing member is a triple coil wire, with theoutermost coiled wire serving to move the debris proximally from thesite, out of the body. Implementation of the Passafaro device requiresthe replacement of a standard guidewire with a guidewire incorporating aspecially shaped guide section, in order to steer the exposed cuttingsurfaces to clear the lumen.

The prior art described does not disclose a device suitable for reachingnarrow vasculature or lumens within the body in order to clear occlusivematerial, the device having shielded cutting elements to protect thevessel wall, the device serving to ensure partial to complete evacuationof the removed occlusive material by implementation of aspiration andinfusate pumping means, capable of achieving and maintaining adequateaspiration vacuum levels and adequate infusate and aspiration flowrates, with the aspiration pumping forces generated by a screw pumpcontained within and running substantially the length of the insertedcatheter body, capable of being used with a conventional guidewire.

It is the intent of this invention to overcome the shortcomings of theprior art in creating a flexible catheter system capable of providingadequate flow rates while extended into and conforming to the moretortuous regions of the vasculature of the living being.

SUMMARY OF THE INVENTION

It is an object of this invention to provide an efficient manner for theremoval of obstructions in a vessel or lumen. This is achieved byproviding an assembly for debris removal, incorporating an “Archimedes”screw pump to aspirate and clear debris from the body.

It is another object of the invention to provide a safe manner for theremoval of obstructions in a vessel or lumen. This is achieved byproviding a device wherein the cutting surfaces are shielded from directcontact with the lumen or vessel wall, and provisions are taken toprevent occlusive material from traveling further away from the site andinto the body. Furthermore, provisions are made to minimize associatedblood loss in the procedure, both in operation of the device as well asin the duration of time required for the performance of the procedure torestore patency to the vessel.

It is yet another object of the invention to provide a small diameterwire guided catheter, which can safely remove obstructions in a vesselor lumen which are located at a distance from the path of the guidewire.This is achieved, for example, by providing an embodiment of a catheterhaving a flexible portion containing a working head, which can laterallyextend away from the guide wire such that the working head portion ofthe catheter can come within a closer proximity of the obstructivematerial to more effectively remove it from the vessel.

It is yet another object of the invention to be able to safely removeobstructions in a vessel or lumen that contain a high percentage offibrous content such as fibrin without winding such obstructions into anagglomerate that could obstruct the aspiration pump. In one embodiment,the aspiration pump features a wire wound about a core member in ahelical fashion, both being disposed within a catheter jacket. Thisobject is achieved by rotating the helical wire and core member atdifferent rotational speeds, by varying the rotational speed of thehelical wire and/or the core member, by providing different directionsof rotation between the helical wire and core member, by rotating thehelical wire only and not rotating the core member, and by providing alarge clearance between the helical wire and the inner wall of thecatheter jacket.

These and other objects of this invention may be achieved by providing asystem for opening a lumen in an occluded or partially occluded vessel,e.g., a blood vessel of a living being's vascular system locateddownstream of another blood vessel, e.g., the aorta, from which bloodwill flow to the occluded blood vessel. In one embodiment, the systemmay feature a catheter assembly having an aspiration means, andoptionally, an infusate delivery means. In a preferred version, theaspiration means is a version of a flexible screw conveyor.

In one embodiment, the system has a working head to facilitate thrombusremoval. The working head may physically manipulate the thrombus (e.g.,a macerating head, a cutting head, etc.) or the working head may affectthe thrombus without making direct contact to the thrombus along thevessel wall (e.g., by creating currents to aid in aspiration, or deliverinfusate jets, etc.) in order to remove the thrombus. In a preferredversion, the working head is shielded within the catheter body, and onlyacts upon material that is pulled into openings strategically placed andsized in the catheter.

The device incorporating a helical screw pump that serves as a flexiblescrew conveyor is capable of navigating the more tortuous regions of thevascular system. The flexibility normally interferes with the operationof a screw pump; because as the catheter distorts in the flexed/stressedregion, forming an oval shape in cross section, resulting in a largerclearance between the helix and the surrounding jacket. The presentinvention overcomes this drawback by rotating at a sufficiently highrate to overcome the pumping losses that occur in the flexed regions.Furthermore, pumping losses at the flexed region are minimized by thelarge number of windings for the helical pump system.

In an embodiment, the cutting surfaces may be shielded, such that theyare not able to come in contact with the vessel wall, but may serve tosever tissue and other material that is drawn into the device by theaspirating force created by the helical pump.

In yet another embodiment, the system comprises a wire-guided mono-railcatheter with a working head mounted on a flexible portion of thecatheter that can laterally displace away from the guide wire tofacilitate thrombus removal. The working head may be operated toseparate and move away from the guide wire to come within a closerproximity of the obstructive material to more effectively remove it fromthe vessel. This embodiment allows relatively small diameter cathetersof the subject invention to remove obstructive material from vesselsthat are much larger in diameter.

In yet another embodiment, the amount of lateral displacement of theworking head from the guide wire can be controlled and adjusted by theoperator to tune the activity of the device to effectively treat andremove debris within various sized vessels.

DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a perspective view of the catheter assembly.

FIG. 2A depicts a cross-section view of the catheter assembly.

FIG. 2B depicts an end on, cross-section view of the infusate catheterassembly at the dashed line 2B of FIG. 2.

FIG. 2C depicts an end on, cross-section view of the aspiration catheterassembly at the dashed line 2C of FIG. 2.

FIG. 3 depicts an alternate embodiment of the catheter assembly.

FIG. 4 depicts an enlarged cross-section view of the distal portion ofthe aspiration pump assembly placed in a vessel of a living being, andone embodiment of the distal end of the catheter assembly having aflexible atraumatic tip used in conjunction with a distal protectionmeasure.

FIG. 5 depicts an enlarged view of an alternate embodiment of the distalend of the catheter assembly.

FIG. 6 depicts an enlarged partial cross-section view of a portion ofthe catheter assembly.

FIG. 7 depicts an enlarged view of the distal portion of one embodimentof the aspiration catheter placed in a vessel of a living being.

FIG. 8 depicts an enlarged view of the distal portion of one embodimentof the aspiration catheter operating to remove debris from the vessel ofa living being.

FIG. 9 depicts an end on, cross-section view of the aspiration catheterassembly within the vessel of the living being.

FIG. 10 depicts an end on, cross-section view of the aspiration catheterassembly operating to remove debris from within the vessel of the livingbeing.

FIG. 11 depicts an alternate embodiment of the catheter assembly havinga means for adjusting the degree of active separation between theguidewire and working head.

FIGS. 12A and 12B depict an embodiment of the safety mechanism of thecatheter assembly in a low pressure or closed mode, and high pressure oropen mode, respectively.

FIG. 13 depicts an alternate embodiment of the catheter assembly withthe capability of independently operating the aspiration windings, thecore tube, and the infusate windings with respect to each other.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The present invention provides an assembly having a sufficiently narrowcrossing profile (for example, the cross-section of the inserted deviceat its widest point), and also having adequate flexibility such theinvention is capable of operating while flexed and navigating intoregions of a body of a living being in order to clear occlusivematerial, e.g. blood clots or plaque accumulation in a blood vessel orlumen.

The following description describes the catheter assembly, componentsand features depicted in the figures, wherein like numbers refer to likecomponents.

In one embodiment, the catheter assembly features a pair of rotaryhelical pumps, the helical pumps serving the function of aspiration andinfusate delivery, and may be operated independently by distinct sourcesof rotary power (e.g., electrical motors, air turbine, hydraulic, etc.).In an embodiment, the rotor for each of the helical pump mechanisms(infusate and aspiration) are operatively coupled to a single source ofrotary power though each may operate independently (e.g., through theimplementation of independent transmission mechanisms, (e.g., clutchpacks, adjustable or fixed gearing, etc.).

In another embodiment, the aspiration pump only features a helical pumpmechanism coupled to a source of rotary power. In this embodiment, anydelivery of an infusate liquid may be accomplished by other methods,such as by high-pressure fluid delivery utilizing a reciprocatingpositive displacement pump in order to provide an adequate infusateliquid flow rate. Alternatively, no infusate delivery may be required,accordingly, an embodiment lacking provisions for delivery of aninfusate may be created having only the aspiration pump.

In one embodiment, as depicted in FIG. 1 and in exploded cross-sectionin FIG. 2A, the catheter assembly 1 is driven by a single motor 26 orother source of rotary power (e.g., electrical motor, air pressureturbine, hydraulic turbine, etc.), effectuating the rotation (i.e., viaa gearing mechanism or transmission) of a hollow driveshaft 12. Thedrive shaft may be operatively coupled on its proximal side 12 to aninfusate helical pump 38, and in fluid communication with an infusateliquid reservoir (not shown). The drive shaft 12 may also be operativelycoupled on its distal end 14 to an aspiration helical pump 40, which maybe directed into the patient and in fluid communication with thetreatment area. The distal portion of the aspiration pump is shown ingreater detail in FIG. 4, as will be discussed.

In another embodiment, as can be seen in FIG. 3, a motor 326 or othersource of rotational power may serve to actuate the driveshaft 331,either directly (as shown) or indirectly through a transmission or gearmechanism (not shown), and the drive shaft may extend distally towardsand into the body (not shown). In this embodiment, a single driveshaft331 drives both the aspiration pump 340 and the infusate pump 338. Theproximal portion 348 of the driveshaft 331 features a helical infusatepump 338, which has infusate windings 344 that, when rotated by thedriveshaft 331, create infusate fluid flow distally towards the bodyfrom an infusate source 352. At the distal end of the infusate windings,the infusate liquid is directed through a port 330 into a hollow lumenof the core tube 342 forming the distal portion 350 of the driveshaft331. The distal portion of the driveshaft features aspiration windings346 for a helical aspiration pump 340.

In use, the infusate fluid is pressurized by the rotating positivedisplacement action of the infusate pump 338, and the infusate fluid isthereby directed through port 330 into the hollow lumen core tube 342 ofthe aspiration pump 340 and is delivered at the distal end of theassembly (as will be discussed later).

In a similar fashion as the infusate pump, the distal portion 350 of thedriveshaft 331 features a hollow lumen core tube 342 around which iswound a coiled member to form aspiration windings 346 for a helicalaspiration pump 340. As the single driveshaft 331 is rotated, theaspiration windings 346 forming a coiled member rotate within a catheterjacket 358, which causes the aspiration of debris proximally, which maythen be directed towards a waste reservoir 354 by a waste lumen 356.

With reference to FIG. 2A, though applicable to any of the describedembodiments, the assembly may incorporate a gear mechanism 28 ortransmission operatively placed between the motor 26 and the drive shaft12, wherein the gear mechanism serves to transfer a rotary power appliedinto rotation of the driveshaft 12 and the associated helical pumprotors (i.e., in a 1:1 ratio). Alternatively the gearing mechanism mayserve to amplify the torque or turning power available for rotating thehelical pump mechanisms (by a reduction in gearing of the motor relativeto the helical pump rotors (e.g., 2:1 or 3:1, etc); most preferably, thegearing mechanism may serve to increase effective gearing in order toincrease the rotational speed of the driveshaft (e.g., 1:2, 1:5, 1:50,etc.), so that a given number of turns by the motor will result in moreturns of the helical pump rotors. A preferred embodiment features anincrease in effective gearing to ensure that the small diameter helicalpump rotors turning within the catheters are able to achieve adequateflow rates and pressures, as will be discussed.

The helical pump rotors generally, and as utilized for the infusate pumpand aspiration pump of this assembly, are designed to turn within asurrounding jacket (e.g., a catheter or lumen), such that as the turningof the helical rotor occurs, a positive displacement pumping action isproduced by the spirally wound helical pump rotor. This principle isbased on an Archimedes pump or screw pump system. The screw pump systemis capable of compact, powerful delivery of a substance. Furthermore,the screw pump is also effective at delivery of fluids and particulates,and is relatively unimpeded by the presence of solid materials orforeign debris. One benefit of the screw pump design is that the helicalpumps are capable of transporting fluids or particulate materials havingdimensions less than the spacing between the windings of the pumpwithout clogging. A further benefit of the screw pump design is that themechanical transmission of torque through the helical rotor may alsoserve to macerate or reduce the fragment size of the debris to moremanageable levels, allowing material that would otherwise be too largeto be transported.

The effectiveness of a screw pump is dependent upon minimizing theamount of leakage that occurs between the helical pump rotor and thejacket. As will be appreciated by those skilled in the art, the rotationof a helical coil wire creates an Archimedes-like pumping action. Forexample, the infusate pump 38 of the present invention depicted in FIG.2A and in cross-section in FIG. 2B creates a pumping action to aid incarrying an infusate liquid down an annular space or passageway 45,located between the infusate catheter jacket 5 and the infusate helicalrotor, comprising a helical coiled member or wire 23 and an infusatecore member 9.

As a similar example, the aspiration pump 40 of the present invention isa helical pump mechanism as depicted in FIG. 2A, an expanded view inFIG. 4, and in cross-section in FIG. 2C. The aspiration pump 40 servesto create a pumping action to aid in carrying fluid and/or occlusivematerial proximally away from the treatment site, through the rotationof the windings of the aspiration coiled wire 49, which is arrangedbetween the hollow aspiration core lumen 51 and the aspiration catheterjacket 53. Additionally, the hollow aspiration core lumen may allow thedelivery of high pressure fluid to the distal end of the device. In thisembodiment, the crossing profile of the inserted catheter remains smallenough to reach into the more tortuous vasculature.

In particular, the ability of the helical coil wire 23 to deliver fluidflow is a function of: (a) the rotation speed of the helix, (b) theswept volume of the helix (the swept volume of the helix being thevolume of fluid entrapped between the coils of one pitch of the helix),and (c) the leakage or backwards flow along the helix due to theclearance between the helical coiled wire 23 and the infusate catheterjacket 5, as well as the clearance between the helical coiled wire 23and the infusate core 9. If the clearances are reduced to zero (andconsequently the leakage is reduced to zero) the pump can act as a verystiff positive displacement pump, that is, it can deliver flow at alarge range of output pressures regardless of the inlet pressure.Minimizing leakage is necessary to ensure suitable performance as afluid delivery catheter system.

For a flexible helical pump, there is preferably some clearance betweenthe rotating impeller or rotor of the helical pump, and the surroundingjacket. This clearance is required to ensure flexibility of the helicalpump, to ensure the free rotation of the rotor while the pump isdistorted by a bending force. The clearance required to ensure adequateflexibility and function of the catheter may be as much as 33% of therotor diameter, but is typically around 10% or less. That is, theclearance between the rotor and the surrounding jacket will naturallyvary as a bend is introduced, creating an ovalized cross-section in theouter jacket. The gap created through the distortion results in agreater tendency for backward leakage; furthermore, rotor turningresistance is increased due to greater friction through the narroweddimension of the ovalized cross-section, and the rotor will resist theflexing force applied, creating more frictional losses. In order tocompensate for the increased clearance as a consequence of the gapcreated by the flexed assembly, it is beneficial to increase therotational speed of the helical rotor, to minimize backwards leakage.Other factors that influence the amount of backwards leakage in thehelical pump system include the viscosity of the liquid being pumped, ashigh viscosity (thicker) fluids will not be able to leak through the gapas easily as a low viscosity (thinner) fluid; also the size and numberof windings of the pump rotor are factors affecting backwards leakage,as specific amount of leakage past each turn will have less effect byvirtue of the leakage being a smaller proportion of the total fluidpumped than in a design having a smaller rotor, less windings, or lesslength. For windings with a larger pitch (i.e., more space between eachwinding), the flow rate tends to be higher for a given rotational speedthan a narrow pitch (i.e., less space between each winding.)

Particulate having little or no fiber content is carried well by pumpshaving a large range of jacket to rotor clearances. However, particulatethat includes long fibers (such as the fibrin in blood clots) can windaround the spinning rotor and become trapped in an agglomeration thatspins in an axially fixed position thus blocking the pump.

It has been found that, in the case of cores that spin with the rotor,the pump can continue to pump if the rotor to helix clearance is largeenough to allow pumping to continue in the gap between the localagglomerations forming on the spinning components and the jacket bore.Such clearances have to be large compared with the build up of theagglomeration, for example tests on pumps having a rotor diameter ofapproximately 0.04 inch have shown acceptable performance with diametralclearances as great as 50% of the rotor diameter. With pumps having manyhundreds of helix pitches, even larger clearances will function sincethe back leakage across each pitch is so very small.

In cases where the core is fixed, the fibers in the clots do not tend towrap around the spinning rotor in the same way, and thus the rotor tojacket clearance can be reduced significantly, however, to preserve theflexibility, it may be beneficial to provide the levels of clearancedescribed above in reference to ensuring flexibility and function of thecatheter when bent.

Thus the specific design of the helix core and jacket can be selected tocope with the kinds of particulate anticipated, and the degree ofdistortion expected when navigating various anatomies.

For the present invention, high rotational speeds are beneficial inensuring acceptable performance as a catheter designed to be used withinthe vascular system of a living being. For a catheter to be used in theliving being, sizes of around 3 French (F) to 8 F may be appropriate,and vary dependent upon intended usage, for example, 4-5 F for coronaryvessels, 4-5 F for carotids, 5-8 F for femoral arteries, and 3-4 F forcerebral vessels, larger sizes may be required for larger vessels suchas organ and esophageal use.

If an alternative use allows a greater pump diameter or less flexibilityand consequently less clearance is acceptable for the alternative use(e.g., for use in an organ lumen, esophageal use, large diametervessels, etc.), a device according to the present invention featuringreduced rotational velocity may be effective in achieving adequate pumpflow rates. The helical coil pumps of the present invention may alsofeature variable windings or pitches of the coiled wires, in order toenhance flexibility or minimize vibrations, or achieve desired pumpingcharacteristics.

Variable pitches in the windings of a helical pump can also be used tominimize the risk of helix fracture from fatigue, and allow for enhancedflexibility. As the helix revolves in the bent condition induced bynavigating the tortuous anatomy the coils are subject to reversingtorsional stresses. Torsional stress is related to the bend radius ofcurvature and the pitch of the helix, with smaller curvature givinghigher stress and reduced pitch giving reduced stress. It is recognizedthat by providing an aspiration pump having a close pitch distallylocated in the region of the instrument that navigates the most tortuousanatomy the risk of helix, failure can be reduced, and at the same timeenhance flexibility of the distal region with the close pitch.

In one embodiment, as depicted in FIG. 2A, there is attached to andextending proximally away from the driveshaft's proximal end 13 ahelical infusate pump 38 having a helical rotor arranged to turn withinthe infusate catheter jacket 5. This rotor has an infusate core member 9having a helical coil member or wire 23 wound around at least a portionor portions of the length of the core. The infusate catheter jacket 5and rotor extend proximally away from the driveshaft 12, and areoperatively coupled to a source of fluid (not shown) for infusatedelivery. As the drive shaft 12 is rotated by motor 26, the driveshaftin turn causes the rotation of the rotor of the infusate pump 38. Theoperation of the infusate pump 38 causes the infusate liquid to be drawninto the jacket 5 by the rotation of core 9 and helical coil wire 23. Asthe rotation continues, the infusate liquid is conveyed distally furtherinto the infusate annular passageway 45, defined by the windings of theinfusate helical coil wire 23, between the surrounding infusate catheterjacket 5 and the infusate core 9.

As the helical infusate pump 38 is a positive displacement pump in oneembodiment, the windings may not continue for the entire length of theinfusate rotor, rather, the coiled windings may stop or be intermittentand rely on the pressure created by the windings to continue driving thefluid along in the lumen within the jacket. This embodiment may offerincreased flexibility in the regions where there are no windings.Alternatively, the windings may continue for the length of the infusatepump 38, uninterrupted. In an embodiment, the pressurized infusate fluidflow is directed into a central lumen 47 in a hollow driveshaft 12, andfurther down a lumen within a core lumen 51 for the aspiration pump 40,to the distal end of the assembly, where it is delivered into the body(as will be discussed later).

Like the infusate helical pump embodiments discussed, the aspirationpump may also be a helical design, having a rotor comprising anaspiration core member or lumen 51 and a coiled member or wire 49 thatrotate to transport fluids proximally. The coiled member is operativelycoupled to the driveshaft 12, and rotates in unison with the driveshaft12. In one embodiment, the aspiration pump rotor may feature anaspiration coiled member 49 in the form of wire wound into a coil about,or affixed to, the aspiration core lumen 51. In another embodiment ofthe aspiration rotor, there is an aspiration core lumen 51, segments ofwhich feature a helical coiled member 49 wrapped around the core lumen51. In this manner, adequate flow can be achieved, however flexibilityis enhanced, as the regions without the coiled member would be able toconform to sharper bends without affecting flowrates significantly forthe entire pumping mechanism. In an embodiment, the coiled member 49 iswound about a hollow central core lumen 51, but is not affixed thereonor affixed only at the proximal end of the coiled member 49, at or nearthe driveshaft 12. In this embodiment, the torque of the driveshaft 12is transferred along the length of the aspiration coiled member 49 tothe working head 400 at the distal end of the assembly (an enlarged viewof which is shown in FIG. 4, to be discussed later). Furthermore, thecoiled member 49 is spirally wound in an orientation such that as it isrotated, the coil would seek to expand in diameter, tending to unwind,and effectively enhancing the seal of the coiled member 49 against theouter aspiration catheter jacket 53. As the expanded coil member 49 isrotated, some wear occurs at the periphery of the coil wire, maintaininga cutting edge (as will be discussed later).

It is also conceived that it may be desirable to have an aspiration corewire 51 having an aspiration coiled wire 49 positioned about the corewire, where each is free of the other in order to allow for independentmovement. For example, one embodiment provides for a stationary ornon-rotating aspiration core wire 51, over which the aspiration coiledwire 49 can rotate. Such an arrangement is beneficial in cases where theextracted clot provides a high level of fibrous material, which can windaround the revolving core tube and ultimately clog the catheter andinhibit the extraction process. With only the helix revolving, thefibers and other debris pass along the helical pump without winding intoclumps which otherwise block the extraction pumping action. In oneembodiment for this instance, the distal end of aspiration core wire 51can be attached to distal cap 402 in such a manner (not shown) that thecore wire 51 does not revolve with the helical coiled wire 49. In suchan embodiment, the core wire 51 passes through the aspiration coiledwire 49 and into a close clearance hole in the drive shaft 12, thisclearance hole allowing the shaft 12 and the helix to revolve freelyabout the stationary core tube, while allowing the passage of infusatefrom the bore of the shaft to the bore of the core wire 51. Othermethods can be anticipated by those skilled in the art for providingmeans for having a stationary core element and a rotating aspirationelement.

As will be described in more detail later, FIG. 13 illustrates anotherembodiment comprising a catheter assembly that features a pair of rotaryhelical pumps, serving the function of aspiration and infusate delivery,as well as a separately operable rotary core tube extending though theaspiration pump coil 346. The capability of independently operating thecore tube in this embodiment is also beneficial in cases where theextracted clot provides a high level of fibrous materials, as thenon-rotating core tube serves to minimize the extent to which the fiberswind up during operation of the device, where the fibers may otherwisewind around the revolving core tube and block the extraction process. Inthis embodiment, the aspiration helix can rotate in an independentmanner from the core tube. For example the aspiration helix can rotatearound any of: a stationary (e.g. non-revolving) core tube; a core tubethat is rotating in the same direction of the aspiration helix but at adifferent speed; or a core tube that is rotating in an oppositedirection (e.g. counter rotating). In the instance where the aspirationhelical windings are revolving and the core tube is stationary, thefibers would tend to pass along the helical pump without winding intoclumps, which may ultimately block the extraction pathway. It may alsobe beneficial to rotate the aspiration helix and the core tube inopposite directions to further minimize the incidence of fibrousmaterials accumulating upon the core tube and thereby clogging thedevice. Further, the ability to separately control the rotation, or lackof rotation, of the core tube may provide the ability to selectivelydeflect the tip of the catheter to enhance its ability to remove debrisfrom large vessels. Embodiments of this nature will be described later.As illustrated in FIG. 13, each of the aspiration and helical pumps aswell as the core tube may be operated independently by distinct sourcesof rotary power (e.g., electrical motors, air turbine, hydraulic, etc.)to provide the operator with individual control over the direction andspeed of each element. It is also conceived that each of these elementscould be operatively coupled to a single source of rotary power thougheach may operate independently (e.g., through the implementation ofindependent transmission mechanisms, (e.g., clutch packs, adjustable orfixed gearing, etc.).

It should be observed at this point that blockage by clumps of fibrousmaterials or other extracted materials can be affected by the surfaceconditions of the helix 49, the core tube 51 exterior, and interior ofthe catheter jacket 358. It is recognized that the surfaces of theseelements, or other components in contact with body fluids, can be coatedor otherwise treated to enhance their performance with regard to passingmaterials. For example, the application of coating with hydrophilic orhydrophobic properties, or coated with medications such as heparin orPlavix to minimize the likelihood of the attachment of platelets orfibers to any of these elements in contact with extracted materials.

The Fluid Pathway

For those embodiments incorporating infusate delivery, the fluidpathway, begins with a source of infusate fluid (e.g., a reservoir,bottle or supply etc.), preferably located near the patient, mostpreferably located at a level above the patient, in order to preventfree fluid flow backwards into the reservoir, yet not so high thatsubstantial forward free flow occurs without pump activation. Theinfusate pump 38 draws in and pressurizes an infusate fluid.

It is recognized that the infusate may be a liquid (e.g., salinesolution, buffer solution, water, etc.) delivered by the presentinvention in order to flush out debris. A contrast medium may be also bedelivered as infusate in order to aid in guiding the catheter to thetreatment site and direct the application of the present invention atthe treatment site. Delivery of infusate may further include at leastone biologically active agent or therapy (e.g., blood, or other oxygencarrying liquid, drugs/beneficial agents, etc.), a non-exhaustive listof examples of biologically active agents that may be delivered areenumerated in Table 1.

TABLE 1 Examples of Biological Active Ingredients Adenovirus with orwithout genetic material Alcohol Amino Acids L-Arginine Angiogenicagents Angiotensin Converting Enzyme Inhibitors (ACE inhibitors)Angiotensin II antagonists Anti-angiogenic agents AntiarrhythmicsAnti-bacterial agents Antibiotics Erythromycin PenicillinAnti-coagulants Heparin Anti-growth factors Anti-inflammatory agentsDexamethasone Aspirin Hydrocortisone Antioxidants Anti-platelet agentsForskolin GP IIb-IIIa inhibitors eptifibatide Anti-proliferation agentsRho Kinase Inhibitors (+)-trans-4-(1-aminoethyl)-1-(4-pyridylcarbamoyl)cyclohexane Anti-rejection agents Rapamycin Anti-restenosis agentsAdenosine A2A receptor agonists Antisense Antispasm agents LidocaineNitroglycerin Nicarpidine Anti-thrombogenic agents ArgatrobanFondaparinux Hirudin GP IIb/IIIa inhibitors Anti-viral drugsArteriogenesis agents acidic fibroblast growth factor (aFGF) angiogeninangiotropin basic fibroblast growth factor (bFGF) Bone morphogenicproteins (BMP) epidermal growth factor (EGF) fibringranulocyte-macrophage colony stimulating factor (GM-CSF) hepatocytegrowth factor (HGF) HIF-1 insulin growth factor-1 (IGF-1) interleukin-8(IL-8) MAC-1 nicotinamide platelet-derived endothelial cell growthfactor (PD-ECGF) platelet-derived growth factor (PDGF) transforminggrowth factors alpha & beta (TGF-.alpha., TGF-beta.) tumor necrosisfactor alpha (TNF-.alpha.) vascular endothelial growth factor (VEGF)vascular permeability factor (VPF) Bacteria Beta blocker Blood clottingfactor Bone morphogenic proteins (BMP) Calcium channel blockersCarcinogens Cells Cellular materials Adipose cells Blood cells Bonemarrow Cells with altered receptors or binding sites Endothelial CellsEpithelial cells Fibroblasts Genetically altered cells GlycoproteinsGrowth factors Lipids Liposomes Macrophages Mesenchymal stem cellsProgenitor cells Reticulocytes Skeletal muscle cells Smooth muscle cellsStem cells Vesicles Chemotherapeutic agents Ceramide Taxol CisplatinCholesterol reducers Chondroitin Collagen Inhibitors Colony stimulatingfactors Coumadin Cytokines prostaglandins Dentin Etretinate Geneticmaterial Glucosamine Glycosaminoglycans GP IIb/IIIa inhibitors L-703,081Granulocyte-macrophage colony stimulating factor (GM-CSF) Growth factorantagonists or inhibitors Growth factors Bone morphogenic proteins(BMPs) Core binding factor A Endothelial Cell Growth Factor (ECGF)Epidermal growth factor (EGF) Fibroblast Growth Factors (FGF) Hepatocytegrowth factor (HGF) Insulin-like Growth Factors (e.g. IGF-I) Nervegrowth factor (NGF) Platelet Derived Growth Factor (PDGF) RecombinantNGF (rhNGF) Tissue necrosis factor (TNF) Transforming growth factorsalpha (TGF-alpha) Transforming growth factors beta (TGF-beta) VascularEndothelial Growth Factor (VEGF) Vascular permeability factor (UPF)Acidic fibroblast growth factor (aFGF) Basic fibroblast growth factor(bFGF) Epidermal growth factor (EGF) Hepatocyte growth factor (HGF)Insulin growth factor-1 (IGF-1) Platelet-derived endothelial cell growthfactor (PD-ECGF) Tumor necrosis factor alpha (TNF-.alpha.) Growthhormones Heparin sulfate proteoglycan HMC-CoA reductase inhibitors(statins) Hormones Erythropoietin Immoxidal Immunosuppressant agentsinflammatory mediator Insulin Interleukins Interlukin-8 (IL-8)Interlukins Lipid lowering agents Lipo-proteins Low-molecular weightheparin Lymphocites Lysine MAC-1 Methylation inhibitors MorphogensNitric oxide (NO) Nucleotides Peptides Polyphenol PR39 ProteinsProstaglandins Proteoglycans Perlecan Radioactive materials Iodine- 125Iodine- 131 Iridium - 192 Palladium 103 Radio-pharmaceuticals SecondaryMessengers Ceramide Somatomedins Statins Stem Cells Steroids ThrombinThrombin inhibitor Thrombolytics Ticlid Tyrosine kinase Inhibitors ST638AG-17 Vasodilators Histamine Forskolin Nitroglycerin Vitamins E C YeastZiyphi fructus

The infusate may also include solids or semisolids instead of fluid-onlydelivery. The solids may be suspended in solution. In any event, thesolids should be of a particle size acceptable for use in helical pumpsystems, that is, of particle sizes capable of being delivered through ahelical pump as provided. A non-exhaustive list of examples of solids orsemi-solids that may be delivered are enumerated in Table 2.

TABLE 2 Examples of solids or semi-solids capable of being delivered bythe present invention Alginate Bioglass Calcium Calcium PhosphatesCeramics Chitin Chitosan Cyanoacrylate Collagen Dacron Demineralizedbone Elastin Fibrin Gelatin Glass Gold Hyaluronic acid Hydrogels Hydroxyapatite Hydroxyethyl methacrylate Hyaluronic Acid Liposomes Mesenchymalcells Nitinol Osteoblasts Oxidized regenerated cellulose Phosphateglasses Polyethylene glycol Polyester Polysaccharides Polyvinyl alcoholPlatelets, blood cells Radiopacifiers Salts Silicone Silk Steel (e.g.Stainless Steel) Synthetic polymers Thrombin Titanium

The inclusion of groups and subgroups in the tables is exemplary and forconvenience only. The grouping does not indicate a preferred use orlimitation on use of any material therein. For example, in Table 1, thegroupings are for reference only and not meant to be limiting in any way(e.g., it is recognized that the Taxol formulations are used forchemotherapeutic applications as well as for anti-restenotic coatings).Additionally, the table is not exhaustive, as many other drugs and druggroups are contemplated for use in the current embodiments. There arenaturally occurring and synthesized forms of many therapies, bothexisting and under development, and the table is meant to include bothforms.

The infusate fluid becomes pressurized by the operation of the helicalinfusate pump 38 creating a positive displacement pumping action,coupled with the fluid resistance and drag of the infusate fluid intraveling a relatively small bore of both the infusate annularpassageway 45 and the hollow lumen within the aspiration core lumen 51.Upon being expelled from the coils 23 of the infusate helical pump 38,the infusate liquid may be propelled along, under pressure, through thecontinuous lumen 45 defined within the infusate catheter jacket 5 forthe infusate helical pump 38. The infusate liquid is then directedthrough at least one port (not shown) into a central lumen 47 within thehollow driveshaft 12. The central lumen 47 of the hollow driveshaft isin fluid communication with the hollow core lumen 51 of the aspirationhelical pump 40. The pressurized infusate liquid travels through thelumen defined by the hollow core lumen 51, running the length of theaspiration pump 40, and the infusate is delivered through at least oneoutlet port in the working head 400, at or near the distal end of theassembly 1.

The infusate liquid delivery through the outlet port in the working head400 may be in the form of high velocity, directed jets, streams orsprays, as required for a particular treatment methodology.Alternatively, either by reducing the flow rate or by providing a largeenough delivery port or ports, the infusate pressure can be reduced suchthat the infusate liquid is delivered as a gentle wash or lavage,without much velocity to a target area. In the higher velocity deliveryarrangement, the jets or streams may be oriented distally further intothe body, radially away from the device and towards the walls of thelumen or vessel, or alternatively, directed back towards at least oneinlet port for the removal by the pumping action of the aspiration pump.It is recognized that the fluid delivery may forcibly affect thematerial in the vessel or lumen (e.g., relying on currents or turbulenceto fragment or separate the occlusive material or tissue).Alternatively, the target tissue to be treated may be subjected to thetherapy or agent in the infusate fluid, which may cause a desired effectupon the target tissue, such that treatment may be effectuated. Thecharacteristics of the delivered fluid streams are largely determined bythe infusate delivery pressure and the design of the working head at thedistal end (to be discussed later).

In an embodiment wherein the infusate delivery creates debris releasedfrom the vessel wall, the debris may be temporarily held in suspensionin the mixture of bodily fluids and infusate fluid that has beendelivered. In this embodiment, appropriate measures and care may betaken to contain or prevent the release of the generated debris into thebody away from the site. This may be accomplished through the use ofdistal protection devices (e.g., umbrella filters, balloons etc.) as isknown in the art.

Utilizing the various embodiments described herein, opportunities forunique treatment methodologies are available. For example, duringoperation of the catheter, an infusate fluid Containing a biologicallyactive agent, such as a drug (e.g. table 2), or a particulate orsemi-solid material (e.g. table 3) that may serve a benefit uponexposure to the tissue in the region may be introduced as describedpreviously through the infusate fluid. Additionally, the procedure maybe performed such that as the catheter is withdrawn, a column ofinfusate fluid is left remaining in the treatment site. Through theemployment of a distal protection measure which serves to halt the flowof blood in the vessel, the column of infusate fluid is allowed toremain within the vessel for increased effectiveness of the treatment(such as through the longer delivery period of a biologically activeagent to the tissue). The infusate fluid that remains in the region mayallow increased opportunity for beneficial effect of the material orbiologically active agent delivered in the infusate. This effect isespecially noticeable in a situation where distal protection isutilized, as there is reduced or no through flow to quickly dissipate orremove the beneficial material. Additional benefit may be obtained fromlocalized treatment, as opposed to systemic treatment.

In an alternative embodiment, the operation of the infusate pump 38 andaspiration pump 40 create a current or flow pattern that draws inreleased or fragmented occlusive material to the aspiration ports,thereby preventing the debris from traveling through the body away fromthe treatment site. That is, as the debris is generated by a fluid jetdislodging the material, a current flow is created that directs thematerial towards the aspiration port at the working head, andsubsequently removed by operation of the aspiration pump.

In order to remove the occlusive matter debris and particulate materialfrom the body, an aspiration pump 40 is provided in the assembly. Theaspiration pump is most preferably in the form of a helical pump,extending distally from the driveshaft 12 into the body, and is apositive displacement pump. In an embodiment, the rotation of the driveshaft 12 causes the helical coiled member 49 to turn, resulting inconveyance of debris via screw pump fluid transport. The fluid flow ratefor any delivery of infusate fluid may be at the same or different rateas the aspiration fluid flow. Most preferably the rate of aspiration isgreater than that of the infusate delivery, in order to ensure completeremoval of any debris generated. It is recognized that variousembodiments may not deliver infusate, and only aspirate material. Caremay be taken to prevent excessive blood loss and or collapse of thelumen due to unbalanced fluid flow rates.

In the embodiment depicted in FIG. 2A, there is an adjustment device 55in order to maintain the appropriate positional relationship between thedistal end of the coiled member 49 and the working head 400. The workinghead, shown in greater detail in FIG. 4, has at least one aspirationinlet port 404 and is operatively coupled to the aspiration catheterjacket 53, in which the coiled member 49 and the core member 51,together comprising the aspiration pump rotor, are arranged to rotate.As can be seen in FIG. 2A, the adjustment mechanism 55 may include aninner threaded element 59 and outer threaded element 57. Rotating theouter threaded element 57 may result in distal movement relative to theinner threaded element 59 (i.e., unscrewing), the aspiration catheterjacket 53 is then driven distally, as the proximal end of the aspirationcatheter jacket 53 is operatively coupled to the outer threaded element57. Conversely, rotation in the opposite direction causes proximalmovement of the aspiration catheter jacket 53, and reduces any gapbetween the distal end of the coiled member 49 and the end of thecatheter jacket 53. The adjustment device allows control of frictionbetween the rotating coiled member 49 inside the cap 402 of the workinghead 400 located at the distal end of the aspiration catheter jacket 53.Furthermore, the adjustment mechanism 55 allows the proper placement ofthe windings of the coiled member 49 within the working head. Theability to adjust the position of the working head 400 relative to thedistal end of the coiled member 49 is necessary to compensate for theeffects of wear, bending and expansion of the coiled member 49. If thecoiled member is significantly driven up against the inside surface ofthe working head while rotation is applied through the driveshaft 12,friction between the tip of the coiled member 49 and the working head400 may reduce the rotation rate of the coiled member, in addition tocausing excess wear and generating heat. In an embodiment providing forthe adjustment device, an adjustment can be made to the positioning ofthe helical wire 49 relative to the inlet openings of the distal end,and ensure proper operation of the assembly.

As the helically coiled member 49 of the aspiration pump 40 rotates, thedebris and fluid drawn in through the inlet ports 404 of the workinghead is conveyed proximally by the positive displacement action of theaspiration pump 40. Upon reaching the proximal terminus of theaspiration coiled member 49, the aspirant is driven into an evacuationchamber 60 in fluid communication with the lumen of the aspiration pump.In one embodiment, the evacuation chamber 60 may be a waste collectionvessel (e.g., a bag, bottle, receptacle, etc.), or alternatively, theevacuation chamber may be part of a safety mechanism (to be discussedlater) coupled to at least one pressure valve, which may then deliverthe fluid to waste when appropriate.

In some embodiments, e.g. as depicted in FIG. 13, the aspiration pump340 and infusate delivery methodologies 338 may operate independently(e.g., operate at different times, velocities, and rates). In thisembodiment, appropriate precautions may be taken to prevent anyexcessive delivery of infusate that may cause damage to the vessel ororgan (e.g., rupture, hernia, etc.). Alternatively, precautions may betaken to prevent excess aspiration by drawing excessive fluid out fromthe body such that a localized reduced pressure environment is created,potentially causing a vessel collapse. Excess aspiration may potentiallyharm the patient by resulting excessive blood loss, and steps may betaken to avoid this occurrence. In the embodiment with independentaspiration and infusion, it may be useful to activate the aspirationpump 40 for a brief period of time prior to the activation of theinfusate delivery. In this manner, any debris generated, whether throughintroduction of the device, by infusate delivery, or other mechanicalmeans, would not necessarily be forced away from the target site, andinstead could be directed out from the body through the assembly 1.

Indeed there may be a case for some embodiments to have no infusatedelivery at all. This may be the case when extraction is to be thedominant function and no benefit is perceived in incorporating infusate.In such a case the core tube 51 could be more like a wire or filament,and not require the lumen in the center at all, thereby possibly beingnarrower in dimension. Elimination of the central lumen would permit thereduction in the outer diameter of the device and allow access tosmaller blood vessels within the body.

In the embodiment having a single motor 26 or source of rotary power,the aspiration pump 40 may be activated concurrently with the operationof the infusate delivery pump 38. In the most preferred embodiment, theflow rates of the infusate delivery pump 38 will be less than the flowrate of the aspiration pump 40 (e.g., 3:1 ratio of aspiration:infusionrates). In another embodiment, it is also recognized that the rate ofinfusate delivery can be equal to the rate of aspiration in order tominimize blood loss. In any of the embodiments, the safety of thepatient may require steps to prevent debris release, such as through theuse of distal protection devices (e.g., balloons, umbrella filters,etc.) This serves to ensure that the complete removal of the debrisoccurs, and prevents the debris from traveling through the body or bloodstream with potentially harmful or fatal results.

Optimum results can often be obtained by varying the device rotationalspeed in a cyclical fashion. Such a function could be performed by asolid-state device (not shown) that would provide a cyclical voltage tothe motor 26, thereby causing rotational speed to vary over time or in acyclical progression. Waveforms that are likely to be advantageous mightinclude saw tooth forms that ramp the motor speed from zero to fullspeed in a few seconds followed by cessation of motor rotation for a fewseconds and then a repeat of this cycle. Other waveforms might beramp-up-ramp-down combinations. Such waveforms might include periods ofrunning in reverse for short periods. In all these speed variationpatterns, the objective is to dislodge any blockages in the aspirationpathway that might occur and to keep the extraction flow functioning.

The Safety Mechanism

In an embodiment of the invention, for example, as depicted in FIG. 2A,the aspiration 40 and infusate 38 pumps are driven off a singledriveshaft 12, the driveshaft being propelled by a force applied to thedriveshaft (e.g., electric motor, air turbine, hydraulic, etc.). Withthis embodiment among others, incorporation of a safety mechanism 62 maybe beneficial. In operation, the activation of the driveshaft 12 mayrotate both infusate 38 and aspiration pumps 40 concurrently, howeverinfusate delivery through the distal end of the assembly preferably isnot initiated until a safety mechanism 62 is actuated, as will bediscussed.

In an embodiment of the invention, the safety mechanism 62 operates inresponse to a change in pressure in an evacuation chamber 60 in fluidcommunication with the lumen of the aspiration pump jacket 53. As theaspiration pump 40 is activated, the positive displacement pumpingaction of the helical coiled member 49 draws in fluid and debrismaterial from the treatment site, conveying the aspirant proximally,towards the proximal end of the aspiration pump, and eventually throughto the evacuation chamber 60, resulting in a pressure increase therein.

Prior to activation of the aspiration pumping action, the evacuationchamber 60 is subject to the body's blood pressure, as it iscommunicated through the fluid canal between the body and evacuationchamber, as defined by the lumen of the aspiration pump jacket 53. Atthese pressure levels, the safety mechanism 62 is not actuated to enabledelivery of infusate fluid. While the safety mechanism 62 is notactuated, and the infusate pump 38 is rotating, any infusate fluid flowis directed towards a reservoir, rather than into the body. In thisembodiment, the infusate fluid pathway is controlled by the safetymechanism 62 incorporating at least one valve, and preferably a first 64and second 66 valve; the first valve 64 operating in response to thepressure within the evacuation chamber 60. Either of the valves of thesafety mechanism may be controlled electronically or mechanically,operating in response to an increase in pressure within the evacuationchamber 60.

The safety mechanism of an embodiment, as depicted in FIG. 2A, featuresdual valves (first valve 64, and second valve 66) actuated mechanicallyin response to an increase in fluid pressure present in the evacuationchamber 60. In this embodiment, while the safety mechanism is subjectedto lower pressures in the evacuation chamber, the infusate pathway tothe treatment site through the hollow lumen of the aspiration core lumen51 remains available for fluid flow; however, the path having the leastfluid resistance is through the infusate bypass lumen 68 towards a wastereservoir. In this mode, substantially all infusate fluid flow isthrough the first safety valve 64 opening, and is shunted towards thewaste reservoir through waste lumen 56, rather than through the distalarm of the assembly comprising the aspiration catheter 53 into the body.

As the aspiration pump 40 is engaged and conveys fluid and debrisproximally and into the evacuation chamber 60, the positive displacementpumping action results in a pressure increase within the chamber,creating elevated pressure levels above that of the patient's bloodpressure. The first safety valve 64 is then actuated by the pressurewithin the chamber (e.g., electronically or mechanically), and uponactuation, the infusate bypass lumen 68 fluid pathway that facilitatedinfusate flow directly towards the waste lumen 56 is sealed off,consequently the infusate fluid is directed towards the distal end andtowards the treatment site via the hollow lumen within the aspirationcore lumen 51.

As the pressure continues to increase, a second safety valve 66 isactuated. This second safety valve is actuated when the pressure withinthe aspiration fluid pathway, most preferably within the evacuationchamber 60, is at least as high as is required to activate the firstsafety valve 64. The second safety valve 66 remains closed at the lowerpressures (e.g., blood pressure) and prevents fluid flow from theevacuation chamber towards the waste reservoir. Additionally, the secondsafety valve prevents the reverse flow of infusate fluid from theinfusate bypass lumen 68 and first safety valve 64 into the evacuationchamber 60, and potentially through to the body via the aspiration pump40. The second safety valve, while closed serves to prevent fluid flowbetween the evacuation chamber and the waste lumen 56. Upon actuation ofthe second safety valve 66, fluid flow from the evacuation chamber 60towards the waste lumen 56 is allowed, and continues until the pressureactuating the second safety valve 66 drops below the pressure levelrequired to maintain the second safety valve in an open state. Thesecond safety valve may also be mechanically or electronically actuated.Most preferably, the second safety valve is a mechanical valve (e.g., aball and spring check-valve arrangement) wherein the pressure within theevacuation chamber 60 causes the valve to open and allow fluid flow.

The design of the safety mechanism 62 serves to prevent infusatedelivery without a corresponding activity of the aspiration pump 50. Aspressure created by the aspiration pump is required to enable thedelivery of infusate to the treatment site, should the aspiration pumpsuffer a failure (e.g., due to breakage, clog, etc.) the infusatedelivery is disabled as the aspiration pressure drops, and the infusateliquid is then shunted towards the waste reservoir, rather than towardsthe patient.

In one embodiment, a warning mechanism (not shown) for the operator maybe incorporated, as most likely, the operator would otherwise be unableto determine if the aspiration pump 40 was not operating properly. Thisis due to the fact that the driveshaft 12 will continue to be driven bythe source of power, actuating the pumping mechanism regardless of aclog or failure of the components. This warning mechanism could beaccomplished through the incorporation of a cut-off switch to halt theoperation of the device or more preferably a warning indicator (e.g., alight, sound, etc.) to alert the operator as to the condition of thesafety mechanism, either relying on the actuation of the first safetyvalve, the second safety valve, or alternatively by an entirelyindependent pressure switch in the fluid pathway.

An alternate embodiment of the safety mechanism may be incorporated intothe present invention, in which the device is disabled (e.g., power tomotor removed) if there is an imbalance or deviation from the desiredpressures in the infusate and aspiration pump mechanism. For example, asensor, or monitor could be utilized to track and respond to deviationsin operation of the aspiration pump (e.g., deviations in aspirationpressure, aspiration flow rate, etc.), thereupon triggering a responsiveevent, such as alerting the operator to a malfunction, and/or disablingthe device, at least temporarily. In FIG. 1, there is depicted anembodiment featuring a safety switch 8, that upon a deviation from adesired aspiration pressure, disables the automatic operation of theinfusate pump.

In another embodiment, the safety mechanism 62 serves to prevent harm tothe patient, such as may be accomplished by limiting the rate of flow(infusate and/or aspiration) from either or both of the infusion oraspiration pumps, or limiting or disabling the power source providingfor the rotation of the infusion and/or aspiration rotor(s) of thecatheter assembly. In an embodiment where the device relies on fluidcirculating through one or both of the aspiration or infusate deliverylumens to maintain optimal temperatures, the safety mechanism 62 mayalso serve to prevent operation of the device at rotational speeds whichmight cause harm to the catheter assembly, were the temperatures notcontrolled.

In an embodiment of a safety mechanism 62 depicted in FIGS. 12A and 12B,the safety mechanism is operated by a pressure generated by theoperation of the catheter assembly. Preferably, the safety mechanismresponds to a change in pressure within an evacuation chamber 60, whichis in fluid communication with the lumen of the aspiration pump jacket53. As depicted here, FIGS. 12A and 12B depict the evacuation chamber 60as being directly connected to the aspiration catheter jacket 53,however, it is recognized that the evacuation chamber may be connectedby a separate and distinct intervening lumen branching into theaspiration catheter jacket, or other methods of delivering pressure tothe evacuation chamber as known in the art.

As depicted in FIG. 12A, the safety mechanism is shown in a closed orlow pressure mode. In this mode, the pressure within the evacuationchamber 60 is not sufficient to cause the triggering of sensor or switch706. For example, in an embodiment, a diaphragm 708 material may becaused to elastically expand in response to increasing pressure withinthe evacuation chamber 60. As the pressure within the evacuation chamberincreases, the diaphragm translates this fluid pressure increase intomotion, and as the diaphragm 708 distorts, it may activate a sensor orswitch 706, as can be seen in FIG. 12B.

The pressure increase within the evacuation chamber may be facilitatedby a restriction at the outlet of the evacuation chamber, such as arestriction, baffle, regulator or a pressure sensitive valve. Forexample, while in the low pressure mode of FIG. 12A, the fluid pressurewithin the evacuation chamber 60 is not high enough to cause the rapidescape of fluid through the baffle 710. The baffle 710 is constructed asa hollow lumen having internal projections which serve to slow the flowof low pressure fluid through the length of the baffle. As the pressureupon the fluid is increased, the fluid flow through the baffle 710 mayincrease in velocity, thereby allowing increased quantities of fluid toescape from the evacuation chamber 60. It is recognized that a narrowedlumen or constricted opening provide similar operation as the baffleshown. In any event, the safety mechanism features a flow restrictioncomponent to ensure that adequate pressure is preserved within theevacuation chamber 60 to maintain the elastic distortion of thediaphragm 708 as long as is necessary for proper operation of thedevice. It is recognized that the baffle need not completely block allfluid flow, as long as fluid flow rates, while above a minimum level,will result in the necessary pressure increase within the evacuationchamber 60.

As depicted in FIG. 12A, the baffle 710 should serve to slow fluid flowwhile there is low pressure within the evacuation chamber 60. Aspressure increases, for example, in response to low speed operation ofthe device, the baffle 710 should prevent a matching flow of fluid outof the evacuation chamber, until adequate pressure within the evacuationchamber is achieved; and as the pumping of the aspiration helical pumpcontinues, the pressure within the evacuation chamber increases, causingdiaphragm distortion. At or about the time the diaphragm triggers switch706, the baffle should have less of an effect as at higher pressures,fluid velocity through the baffle should increase, allowing an amount offlow therethrough that matches the flow delivered by the pumping action,as is depicted in FIG. 12B.

Should there be a decrease in the pressure of the evacuation chamber(e.g., due to an obstruction in the fluid pathway leading to theevacuation chamber, or loss of pumping capability), the baffle 710 anddiaphragm 708 will compensate by reverting back to the low pressure modeof FIG. 12A, preferably in proportion to the decrease in pressureexperienced within the evacuation chamber 60. As the diaphragm 708disengages from the sensor or switch 706, or alternatively triggers asecond sensor (not shown), indicating a reduction in pressure within thechamber 60, the device responds by at least partially disabling thecatheter assembly, such as by reducing or eliminating the source ofpower, thereby reducing pumping speeds or completely eliminating anypumping action altogether.

The Working Head

The assembly 1 features a working head 400 at the distal end of theassembly to be introduced into the patient for the procedure; examplesof the working head are depicted in FIGS. 4, 5 and 6. As can be seen inFIG. 4, the working head 400 is operatively connected to the aspirationpump 40 of FIG. 2A. The working head features a cap 402 physicallyattached to the aspiration catheter jacket 53, and the helical coils ofthe aspiration coiled member 49 rotating within the cap. The workinghead in FIG. 4 is depicted placed in a vessel 424 of a living being, theassembly having been advanced as a monorail over a guidewire 430, inorder to arrive at the treatment site, shown here having occlusivematerial 426, which may be a lesion, deposit or stenosis. At or near thedistal end of the guidewire may be a distal protection measure 444, asshown. The distal protection measure serves to prevent debris fromtraveling away from the treatment site, such as by preventing the freeflow of fluid with a balloon (as shown) or alternatively, such asthrough the use of a filter mechanism to capture any debris or loosenedocclusive material 426. It is recognized that the use of the device maynot require the use of distal protection, relying on the safe aspirationof fluid and occlusive material through the operation of the aspirationpump as described earlier.

FIG. 5 depicts another embodiment of the cap portion of the workinghead. As illustrated, the cap 502 provides at least one aspiration inletport 504 to be located at or near the distal end of the assembly,thereby allowing material to pass through the inlet port 504, and, withreference to FIG. 2A, into contact with the aspiration coiled member 49comprising the rotor of the aspiration pump 40 within the aspirationpump jacket catheter 53. The cap 502 also features an infusate deliveryport 506, and a guidewire following means 508.

In a preferred embodiment, as depicted in FIG. 4, as the coiled member49 of the aspiration pump rotates, the positive displacement actiondraws fluid and debris into the windings of the coiled member 49 throughthe aspiration inlet port 404. These inlet ports may be sizedappropriately to ensure proper operation of the device. Inlet portsinappropriately sized by being too small in diameter will not allowocclusive material to enter into the aspiration jacket, similarly thosethat are too large may allow too much material to enter into the jacketand potentially clog the aspiration pump. Furthermore, adequate suctionvelocity may be maintained through the inlet ports. That is, the numberand size of the inlet ports may be made appropriate for the particularuse, thereby not spreading the aspiration force over too large a surfacearea, which would otherwise result in too slow a velocity through theinlet ports to be effective in drawing in occlusive material. Thenumber, size and shape of the inlet ports is determined empirically, andvaries with the amount of suction created at the distal end by therotation of the aspiration pump rotor, and the viscosity of the blood ormaterial to be drawn in. Furthermore, the design of the rotatingelements might determine the appropriate size and number of inlet ports(to be discussed later). Generally, a balance may be struck between toolittle suction velocity and too much material entering into the catheterjacket. An appropriate number and sizes of inlet ports should result infragmentation of occlusive material into manageable sizes for theaspiration pump (i.e., less than the distance between adjacent windingsof the coiled wire), and further provide for adequate flow ratesgenerated by the rotation of the aspiration pump.

In one embodiment of the working head of the assembly, as depicted inFIG. 4, the inlet ports 404 have a sharp cutting edge forming theperiphery of the port. In this embodiment, any material drawn into thewindings of the aspiration rotor may be cut by the sharpened edge of theinlet ports, forming fragments of a size capable of being conveyed bythe aspiration pump. The inlet ports may sit flush with the outerdiameter of the jacket, or alternatively, and preferably, countersunk inorder to prevent contact of a sharpened cutting edge with non-targetedtissue. The countersinking process may inherently produce a cuttingedge, as can be seen in the depiction of a counter sunk inlet port 404of FIG. 4.

In one embodiment, the aspiration coiled member 49 may also feature acutting edge. In this embodiment, the coiled member may be at leastpartially formed having an acute edge that acts upon the target tissue.In a preferred embodiment, the aspiration coiled member at or near thedistal end of the assembly has a cross-section comprising at least oneedge (e.g., planar, triangular, rectangular, square, etc.) that servesto sever the tissue against the inlet port 404, cap 402, or aspirationcatheter jacket 53, macerating the material into manageable sizes forthe aspiration pump as the coiled member rotates.

In the alternative embodiment of an aspiration coiled member not havingan edge (e.g., a round, pear shaped, oval cross-section etc.) therotation of the coiled member may serve to sever the tissue against theaforementioned edge of an aspiration inlet port. In this or otherembodiments, by rotatably conveying the aspirant material, the fibrin inthe material may be further reduced into smaller fragments by themaceration as a consequence of the rotation of the cutting edge of thecoiled member 49. The maceration occurs where thrombus material isfurther severed by the individual windings of the aspiration coiledmember pinching the thrombus material against the inner surface of thecap 402 or the extraction catheter jacket 53.

In a preferred embodiment, depicted in FIG. 2, where the proximal end ofthe aspiration coiled member 49 is affixed only to the drive shaft 12 atthe proximal end of the coiled member, as the torque is transmitted thelength of the coiled member, there is a tendency for the coiled memberto unwind, resulting in a larger outer diameter of the coiled member.The expansion of the coiled member is limited by the aspiration catheterjacket 53 entraining the aspiration pump mechanism 40. As the coiledmember is rotated, and wear occurs between the coiled member 49 and thejacket 53, a cutting edge may be maintained upon the outsidecircumference of the coiled member, allowing it to more easily sever thetissue drawn in through the inlet port 404. Furthermore, the unwindingthat occurs as the coiled member 49 is torqued also forces the coiledmember outwards as it tends to unwind away from the central core lumen,and against at least one inlet port 404 at the distal end, furtherenhancing the ability of the assembly to fragment the occlusive materialinto more manageable fragment sizes.

FIG. 6 features an alternative embodiment of a working head 600,specifically the distal portion of the assembly designed for insertioninto a patient for a procedure to remove occlusive material. Workinghead 600, of FIG. 6 may be operatively connected to the aspiration pump40 of FIG. 2A, FIG. 3, or FIG. 13, or to other aspiration mechanismsknown in the art. The working head 600 consists of a can portion 602physically attached to the aspiration catheter jacket 53, with thehelical coils of the aspiration coiled member 49 rotating within thecatheter jacket 53 and can 602. As illustrated, the can 602 provides atleast one aspiration inlet port 604 to be located at or near the distalend of the assembly, thereby allowing material to pass through the inletport 604, and into contact with the aspiration coiled member 49 withinthe aspiration pump jacket catheter 53. In one embodiment, the canportion 602 has an external diameter that is approximately the same asthe adjacent catheter jacket 53. However, another embodiment may have anenlarged can portion, e.g. of greater diameter, (not shown) that wouldallow the device to more effectively treat occlusive materials in largerdiameter vessels. The can may simply be a distal portion of the catheterjacket 53, or alternatively, the can may be an annular structure affixedto the distal end of the aspiration catheter jacket 53.

In practice, the working head is typically guided to the desiredlocation within the body of a living being over guidewire 430, which maybe loaded through the flexible atraumatic tip 616 and through theguidewire lumen 612. In another embodiment, guidewire lumen 612 can be amono-rail guide, in which case the guidewire would travel for a shortdistance within lumen 612 until exiting a short distance more proximalfrom the end of the catheter (not shown). It is recognized that one ormore radiopaque markers may be incorporated into the various locationson the device (e.g. can, retention bands, atraumatic tip, etc.) to allowvisualization techniques to be utilized when placing the catheter.

The working head 600 may also feature an angularly displaced portion 680of the working head 600. In one embodiment, the angularly displacedportion 680 of the working head consists of an aspiration coiled wire 49and hollow aspiration core wire 51 that, upon rotation causes thecatheter jacket 53 to deflect away from (e.g., lateral, radial ororthogonal to) the guidewire lumen 612. There may be a benefit toproviding an aspiration core wire 51 and coiled wire 49 that arepre-bent, imbalanced, or otherwise arranged to provide an enhancedmovement of the working head 600 upon rotation of the core wire 51 andcoiled wire 49. A pre-bent section may be laterally displaced by someamount, as shown in FIGS. 6 and 7, while at rest and absent the rotationof the aspiration pump components. Upon applying rotation to theaspiration pump components, the working head 600 will be caused to belaterally displaced from the guidewire a varying amount, as the rotationof the core wire 51 and coiled member 49 causes the working head toaffect movement, in forms such as vibration, arc, orbit, scan,oscillation or precession. As stated earlier, pre-bending a portion ofthe device may enhance the direction, and extent of lateral displacementof the working head 600 away from the guidewire 430.

As has been described previously with reference to FIG. 1, the catheterassembly of FIG. 6 may similarly be driven by a single motor 26 or othersource of rotary power (e.g., electrical motor, air pressure turbine,hydraulic turbine, etc.), effectuating the rotation (e.g., via a gearingmechanism or transmission) of a driveshaft 12. The driveshaft 12 may behollow, and also may be operatively coupled on its distal end 14 to anaspiration helical pump 40, which in turn operates the helical coils 49causing them to rotate within catheter jacket 53. As a result ofrotation, and possibly combined with the angularly displaced portion 680of the working head 600, the rotation of the aspiration helical pumpwill cause a portion of the working head to displace away from and thenback towards the guidewire lumen 612. As a function of the rotationalspeed of the aspiration helical pump components, specifically, the corewire 51 and coiled wire 49, within the aspiration catheter jacket 53 andcan 602, rotating at approximately 10,000 to approximately 150,000 RPM,preferably about 60,000 to about 110,000 RPM, the working head will seekto precess (i.e., via a precession path) away from the guidewire lumenand effectively scan the vessel as will be illustrated later. The rapidrotation of the aspiration pump may cause movement of the working head(e.g., vibrational, precessional, arcing, orbital movement) in afrequency range that is heavily dependent upon the materials of thedevice, as well as the local conditions, where the frequency of themovement of the head will correspond to, or be less than that of therotational speed of the aspiration helical pump. It is also recognizedthat secondary or compound movement may occur during operation, forexample, while the working head is moving as described previously, theworking head may also be subject to additional movement patterns, albeitof smaller magnitude than the first movement. For example, it isrecognized that the smaller magnitude movement may be an orbitalmovement occurring as the working head is traveling along a largerorbit, in a fashion similar to epicyclic movement. By controlling thedisplacement shape of the angularly displaced portion 680 of the workinghead, the movement of the working head can be optimized to best treatthe occlusive material. It is recognized that the pre-bent section cantake on a variety of shapes, such as being formed to mimic a sine wave,half of a sine wave, a square wave, a step function, a helix, corkscrewor any other 3-D pathway, or other desirable profiles.

In one embodiment, a flexible connector (e.g., flexible spring orresilient material) section 674 of the working head which is attached toat least the distal end of can 602 by means of retention band 670 orother fixation methods (e.g., adhesives, welding, soldering, etc.)provides the flexibility for the can portion 602 of the working head 600to deflect away from the guidewire 430 and guidewire lumen 612. Thisflexible section can be constructed of a variety of resilient orflexible materials known in the art (e.g. steel, nitinol, plastic,etc.). It is also considered that the flexible spring section could becoated or covered with another material, such as polymer shrink wrap, toprovide a fluid tight seal, and/or prevent the coil springs fromtrapping tissue or debris. Alternatively, the flexible section 674 maybe incorporated into the flexible atraumatic tip 616, such as bylengthening the tip 616, where the tip is of a suitably flexiblematerial and design, and where the tip is attached directly to retentionband 670 thereby serving the function of a flexible spring.

Varying the construction of the apparatus will allow one to tailor theextent to which the working head 600 can be laterally displaced awayfrom the guidewire 430 or guidewire lumen 612. For example, the flexibleconnector material's length and construction may control the extent towhich the flexible connector is able to deform in allowing lateraldisplacement or movement of the working head 600, relative to theguidewire 430, or guidewire lumen 612. Also, the amount of lateraldisplacement of the working head 600 may also affected by the length ofun-attachment 622 as determined by the distance between the points atwhich the working head 600 is connected to the guidewire 430 orguidewire lumen 612. This un-attached region is depicted with moreclarity in FIG. 7, where attachment points 660 and 662 define theun-attached region of the catheter. Additionally, the degree of angulardeflection of section 680, along with the flexibility of catheter jacket53 may combine to determine how far the can 602 is capable of deflectingfrom the guidewire lumen. These factors are not exhaustive of themethods by which the lateral displacement may be controlled, forexample, it is recognized that a tether as shown in FIG. 11, may beincorporated into the device to limit the extent of displacement (to bediscussed later). In another embodiment, there may be a singleattachment point, where a guidewire following means is employed to guidethe catheter along the guidewire, and the rest of the catheter is freeto move independently from the guidewire. It is recognized that at leastone tether may be utilized along with this embodiment as well.

As the coiled member 49 of the aspiration pump rotates, the positivedisplacement action draws fluid and debris into the windings of thecoiled member 49 through the aspiration inlet port 604. As previouslydescribed, these inlet ports can be sized to optimize and ensure properoperation of the device. As also described previously, the shape andsharpness of the inlet port 604 can be designed to cooperate with aninternal cutting element (e.g. aspiration coiled wire 49, cutting rotor,helical blades, shaver, or other cutting elements known in the art.) tobest cut and fragment the occlusive material while at the same timeminimizing any unintended trauma to the healthy tissue of the livingbeing. In general, the device provides a safe and reliable means ofbreaking down occlusive material (e.g. plaque, thrombus, etc.) with anexposed rotating cutting element. The rotating cutting element mayconsist of the helical system shown in this embodiment or mayadditionally utilize rotating blades, rotors, impellers or other meansknown in the art treating occlusive materials (e.g., U.S. Pat. Nos.4,696,667; 5,261,877; 5,074,841; 5,284,486; and 5,873,882).

It is recognized that the various embodiments described herein mayincorporate distal protection, for example as shown in FIG. 4, thedistal end of the guidewire may incorporate a distal protection measure(e.g., balloon, filter, etc.) to prevent debris from traveling away fromthe treatment site.

FIG. 7 features an embodiment of distal end of the assembly working head600 depicted as placed in a vessel 424 of a living being, the assemblyhaving been advanced as a monorail over a guidewire 430, in order toarrive at the treatment site, shown here having occlusive material 426,which may be a lesion, deposit or stenosis. As is shown, the can portion602 of the working head 600 is deflected slightly away from guidewirelumen 612. The guidewire lumen attaches to the catheter jacket 53 atattachment location 660 and the guidewire lumen 612 attaches to thedistal portion of the working head at location 662. During operation thecan portion 602 of the working head is caused to deflect away from theguide wire as a result of the rotation of the helically wound wire 49,and optionally, a pre-bent shape of the rotating components, which maycause the working head to affect movement, such as precess or orbit, andthereby move the working head 600 into a new location 602B (FIG. 8)within the vessel to better treat the occlusive material (in a mannersimilar to a jump rope). The movement of the working head may be limitedas the catheter components (e.g., jacket, flexible connection andworking head, encounter the guidewire or guidewire lumen. It isrecognized that the path followed by the working head may not be anormal precession pathway or orbit, as during the movement, the catheterwill have to traverse one side of the guidewire, rather than orbitentirely around the guidewire. This orbit or precess pathway may bebiased directionally within the vessel, duct, lumen or other holloworgan structure. For this reason, there may be a benefit to theproviding, in addition to the previously described movement of theworking head 600, rotation along the axis of the catheter (e.g.,manually or automatically rotating the catheter jacket), to allow thecatheter to sweep a larger area, or perimeter of the vessel to removedebris.

FIG. 8 depicts the working head assembly 600 operating within vessel 424of a living being. As described previously the source of rotary powereffects rotation of the aspiration coiled wire 49 within the jacket 53thereby causing a portion of the working head to undergo movement, as itis displaced away from and then back towards the guidewire lumen 612. Asdepicted in FIG. 8, this permits the catheter to expand the region wherethe working head 600 is able to contact and treat occlusive material.Infusate can be delivered into the vessel through the infusate deliveryport 606 as described in previous embodiments. Aspiration of pieces ofocclusive material 626 can occur through aspiration inlet ports 604. Asillustrated, a catheter having a flexible portion and a working head,which can extend away from the guide wire such that the working headportion of the catheter can come within a closer proximity of theobstructive material allows a small diameter wire guided catheter tosafely remove obstructions in a vessel or lumen which are located at adistance from the path of the guidewire.

FIG. 9 depicts an end on, cross-section view of the aspiration catheterassembly 400 of FIG. 2A, within the vessel of the living being 424 as itis guided by guidewire 430. The working head 400 does not provide forthe flexible spring portion, or extended unattached portion. FIG. 10depicts an end on, cross-section view of the aspiration catheterassembly 600 operating to remove debris from within the vessel of theliving being 424. The rotation of the aspiration coiled wire 49 withinthe jacket 53 thereby causing a portion of the working head 600 totranslocate and be displaced away from and then back towards theguidewire 430 and guidewire lumen 612. The precessional action of theworking head 600 causes it to travel along a path (e.g. such as shown bythe path of working head in FIG. 10 represented by diagrammatically byarrow 690 and phantom lines) permitting the relatively small diameterdevice to contact and remove a greater amount of occlusive material froma larger diameter vessel, thereby reducing the amount of occlusivematerial 426B that remains within the vessel after the procedure. Thedevice has the ability to precess, scan or oscillate within the vesselto treat a greater cross-sectional area at each location along thelength of the vessel. It is anticipated that in some situations, thephysical movement of the oscillating working head may help to disrupt orfragment the occlusive material. However, the catheter is designed suchthat by providing the working head with the ability to move closer tothe occlusive debris, the vacuum created at the inlet ports 604, coupledwith the cutting mechanism within can 602 will allow the device to havegreater efficacy within larger vessels. Furthermore, the additivesdescribed previously may optionally be employed with this embodiment(e.g. drugs, such as thrombolytics).

FIG. 11 depicts an embodiment of working head 600 with at least onedeflection-limiting element (e.g., tether) 682 for controlling theeffective area of activity scanned by the movement of the working head600. Other technique for limiting the translational movement of theworking head away from the guidewire 430 or guidewire lumen 612 may beapplied, such as releasably arranged interlocking features, oradjustable slip rings that may be maneuvered to free up the working headfor varying amounts of translational movement. As described previously,the length of un-attachment in combination with the degree of angulardeflection, the flexibility of flexible connector section and theoverall flexibility of the catheter jacket 53 in the region of theworking head 600 all may determine how far the can 602 can deflect awayfrom the guidewire lumen. A deflection-limiting tether 682 can be addedto limit the distance that the can element 602 can travel away from theguidewire 430. This could allow the physician, surgeon, or other deviceoperator to selectively expand the area of activity of the working headto gradually ease the device into large volumes of occlusive material.Despite the intended design of the catheter to not harm healthy tissue,this deflection-limiting tether 682 could serve to prevent the activearea of the working head from contacting portions of the vessel wall. Itcould also be useful in treating vessels that change in diameter overtheir length. The tether could be adjusted to a short length in thesmall diameter portions and lengthened in the larger diameter vesselportions as necessary.

The deflection-limiting tether 682 consists of a filament that isconnected fixably to a portion of the can portion 602 of working head600. The filament extends from the can portion 602 into a hole 686 inlumen 612 and through a pathway 684 in the guidewire lumen back towardsthe proximal portion of the device where a control mechanism (not shown)such as a reel or cam can be used to tighten or release the tension onthe tether. It is possible that the guidewire 430 and the tether 682could share the same lumen along at least a portion of the device. It isalso anticipated that in an alternate configuration the tether could befixably attached to the guidewire lumen at location 686, extend to thecan 602, into a pathway in can 602 (not shown) and then back through thecatheter jacket via a pathway (not shown) to the proximal end of thedevice. A similar mechanism, known in the art could be used to tensionand release tension in the tether. The pathway for the tether allows thetether to move freely. Ribbons, wires, retractable sleeves, and othermechanisms which can actively control the working head of the catheterwith respect to the guidewire or guidewire lumen can also be used tolimit the deflection of the working head.

It must be pointed out that the lateral displacement of the variousembodiments of the present invention is not limited solely tothrombectomy catheters, and particularly rotational thrombectomycatheters. In particular, there may be a benefit to a device capable ofhaving the working head displaced laterally as has been described, wherethe device incorporates an instrument having any other type of workinghead, e.g., fluid jets, atherectomy, rotary cutting, rotary abrasive,balloon angioplasty, a catheter for injecting a restriction-removing ordissolving liquid, an ultrasonic catheter, a laser catheter, astent-delivery catheter, etc., for opening a lumen in an occludedvessel. Thus, a system constructed in accordance with any embodiment ofthis invention may make use of any instrument having any type of workinghead to open the lumen in the occlusive material in the blood vessel.Examples of other devices incorporating working heads are the AmplatzThrombectomy Device designated by the trademark CLOT BUSTER by MicrovenaCorporation, the ANGIOJET device by Possis, the SILVERBAWK device byFoxhollow, the TURBO laser catheter by Spectranetics, the ORBITALAtherectomy catheter by Cardiovascular System and the PATHWAY by PathwayMedical. It should also be pointed out that the working head of thedevice need not even engage the occlusive material, so long as itslumen-opening operation. In short, any type of instrument for opening alumen through the occlusive material can benefit from use in the systemof this invention, i.e., a system which allows a small diameterwire-guided catheter to act upon and treat occlusive material which islocated at a distance from the guidewire. To that end the term “workinghead” as used herein is meant to include any type of device foroperating on an occluded vessel to open a lumen in that vessel to thefreer flow of blood therethrough.

In another embodiment of the device having a working head capable ofbeing laterally displaced away from the guidewire, it is recognized thatby increasing the diameter of the guidewire following means 508, or theguidewire lumen 612, at least in the region of the working head, it maybe possible to provide for movement of the working head, at least to theextent that the guidewire following lumens are able to be displacedrelative to the guidewire.

As described previously, FIG. 13 depicts a catheter assembly featuring apair of rotary helical pumps and a separately operable rotary core tube.This embodiment provides certain advantages and features desirable forminimizing the degree to which fibers and debris may wrap around thecore tube of the aspiration catheter. In these cases, it has been foundto be beneficial to rotate the aspiration helix around a stationary(e.g. non-revolving) core tube. With only the helix revolving, thefibers pass along the core jacket and are driven by the aspirationwindings and helical pump without winding into clumps, thereby reducingthe likelihood that the extraction catheter will clog. It may also bebeneficial to rotate the aspiration helix and the core tube in oppositedirections to further minimize the incidence of fibrous materialsaccumulating upon the core tube and thereby clogging the device.Further, in consideration of the embodiments in FIGS. 6-11 the abilityto separate the aspiration pumping action and the tip deflection actionof the catheter may be beneficial as will be described.

In the embodiment of FIG. 13, the aspiration windings may be operated ata different speed and or in a different direction than the core tube 342to minimize the instance of having fibrous materials wrap around thecore tube. As illustrated, each of the pumps and core tube may beoperated independently by distinct sources of rotary power (e.g.,electrical motors, air turbine, hydraulic, etc.) to provide the operatorwith individual control over the direction and speed of each element. Itis also conceived that each of these elements could be operativelycoupled to a single source of rotary power though each may operateindependently such as through the implementation of independenttransmission mechanisms, (e.g., clutch packs, adjustable or fixedgearing, etc.).

As can be seen in FIG. 13, a motor 326 or other source of rotationalpower may serve to actuate the driveshaft 331, either directly (asshown) or indirectly through a transmission or gear mechanism (notshown), and the drive shaft may extend distally towards and into thebody (not shown). Motor 326B drives aspiration gear drive assembly 704,which causes the rotation of aspiration helix drive 746. As theaspiration helical drive 746 is operatively connected to the aspirationwinding 346, this causes the rotation of the aspiration windings 346within catheter jacket 358. For those instances when it is desirable torotate the core tube, motor 326C drives core tube gear drive assembly702, which causes the rotation of core tube drive 742, which causes therotation of the core tube 342 within the aspiration windings 346 andcatheter jacket 358. For instances where infusate is required for theprocedure, the proximal portion 348 of the driveshaft 331 features ahelical infusate pump 338, which has infusate windings 344 that whenrotated by the driveshaft 331 creates infusate fluid flow distallytowards the body from an infusate source 352. At the distal end of theinfusate windings, the infusate liquid is directed through a port 330into a hollow lumen of the core tube 342 forming the distal portion 350of the driveshaft 331. The distal portion of the driveshaft featuresaspiration windings 346 for a helical aspiration pump 340. In otherembodiments, infusate may not be required for the procedure and the coretube 342 can be replaced with a solid core wire or other suitablematerial and the infusate pump 338 may be eliminated from the device.This embodiment may additionally provide a benefit in the form of alower crossing profile, by reducing the working diameter of theaspiration pump, as the core tube may now be in the form of a narrowfilament or wire.

As described previously, the infusate fluid is pressurized by therotating positive displacement action of the infusate pump and isdelivered at the distal end of the assembly.

In a similar fashion as the infusate pump, the device featuresaspiration windings 346, wound around hollow lumen core tube 342 andhoused within catheter jacket 358 to form helical aspiration pump 340.As motor 326B is rotated, the aspiration windings 346 forming a coiledmember rotate within a catheter jacket 358, which causes the aspirationof debris proximally, which may then be directed towards a wastereservoir 354 by a waste lumen 356. The hollow lumen core 342 can beheld in a stationary position or operated in any suitable speed ordirection when driven by core tube drive 742, gear drive 702 and coretube motor 326C.

With further reference to FIG. 13, the assembly may incorporate gearmechanisms or transmissions, wherein the gear mechanism serves totransfer a rotary power applied into rotation of the drive shafts foreach element in the desired ratio (i.e., in a 1:1 ratio). Alternativelythe gearing mechanisms may serve to amplify or reduce the torque orturning power, for example by a reduction in gearing of the motorrelative to the helical pump rotors (e.g., 2:1 or 3:1, etc,). Mostpreferably, the gearing mechanism may serve to increase effectivegearing in order to increase the rotational speed of the driveshaft(e.g., 1:2, 1:5, 1:50, etc.), so that a given number of turns by themotor will result in more turns of the helical pump rotors or hollowcore lumen.

The ability to separately control the rotational direction and speed ofthe core tube provides several distinct benefits when considering theembodiments shown in FIGS. 6-11. As described previously, working head600 features an aspiration coiled wire 49 (or alternatively aspirationwindings 346) and hollow aspiration core wire 51 (or alternatively coretube 342) that upon rotation causes the catheter jacket 53 to deflectaway from (e.g., lateral, radial or orthogonal to) the guidewire lumen612. In one embodiment, this tip deflection results from the rotation ofthe aspiration core wire with a pre-bent shape formed at the distal end.As the core wire 51 rotates, a portion of the distal end of the catheterdisplaces laterally from the guidewire causing the working head toaffect movement, in forms such as vibration, arc, orbit, scan,oscillation or precession. As stated earlier, pre-bending a portion ofthe device may enhance the direction, and extent of lateral displacementof the working head 600 away from the guidewire 430. By utilizing theembodiment of FIG. 13, the aspiration windings can be operated at thespeed that is optimal for extraction or aspirating debris from thevessel and the core lumen can be operated at the speed and in thedirection that causes the tip of the catheter to deflect (e.g. vibrate,rotate, oscillate, etc.) in the most optimal fashion. In some cases aphysician may choose to not activate (e.g. rotate) the central coretube. In other cases, the physician may choose to slowly rotate the coretube, causing the tip to slowly scan the inside of the vessel. In yetother instances, the physician may choose to rotate the core tube athigh speeds, which may cause the tip to rapidly vibrate within the bloodvessel. The operator may also choose to vary the speed of operation.From the applicant's experience with rotary devices designed to fragmentdebris with in the body of a living being, optimum results can often beobtained by varying the device rotational speed in a cyclical fashion.Such a function could be performed by a solid-state device (not shown)that would provide a cyclical voltage to a drive motor. Waveforms thatare likely advantageous might include saw tooth forms that ramp themotor speed form zero to full speed in a few seconds followed bycessation of motor rotation for a few seconds followed by cessation ofmotor rotation for a few seconds then a repeat of this cycle. Otherwaveforms might be ramp-up-ramp-down combinations. Such waveforms mightinclude periods of running in reverse for short periods. In all thesespeed variation patterns the objective is to dislodge any blockages thatmight occur and to keep the extraction flow functioning.

Guidewire Arrangement

The present invention may be operated either with or without a standardguidewire in place. If no guidewire is to be in place during operationof the instrument, a standard guidewire may be utilized for the purposesof aiding the navigation of the device to the treatment site (e.g.,through tortuous vasculature) using techniques known in the art. Once inplace, the guidewire may be removed, in order to allow operation of thepresent invention. Alternatively, the device may be placed in positionwithout the assistance of a standard guidewire, using catheterizationtechniques known in the art.

In an embodiment where the assembly is to be operated with a guidewirein place, the device may follow along a guidewire running through acentral coaxial lumen within the device (not shown). In a preferredembodiment, the device navigates following a guidewire in a monorailfashion. In the monorail embodiment, the assembly travels alongside theguidewire, and at least a portion of the catheter is operatively coupledto the guidewire. The delivery of the assembly to the target site isaccomplished by the assembly traveling alongside the pre-placedguidewire to arrive at the target destination. This monorail embodimentprovides a further benefit for it allows a central bore of theaspiration core lumen to remain unobstructed for delivery of infusate.In this embodiment, at or near the distal end of the device there isprovided an opening for the guidewire to pass through, and ensures thatdevice follows along the guidewire to arrive at the treatment site.

In the embodiment of the working head of the assembly depicted in FIG.4, the device is arranged to slidably follow the guidewire in monorailfashion, additionally there may be provided an additional exteriorguidewire lumen 412 to ensure the device more closely tracks the path ofthe guidewire, in order to prevent harm to the vasculature of thepatient. This may be accomplished by providing an exterior lumenside-by-side with the aspiration pump, for maintaining close proximityto the guidewire, the guidewire lumen having a distal end locatedproximately of the working head of the device. In this embodiment, thecross-section of the device at the working end is minimized andflexibility is enhanced, further allowing the device to travel moretortuous bends without causing damage to the patient, as at least aportion of the guidewire near the distal end of the assembly is free toflex independently of the aspiration catheter jacket.

In the preferred embodiment of the working head of the assembly depictedin FIGS. 6-8, the device is arranged to slidably follow the guidewire inmonorail fashion, and in these embodiments there is an exteriorguidewire lumen 612 that bridges the gap from the flexible atraumatictip 616 to a more proximal portion of the catheter jacket 53 at location660. This exterior guidewire lumen helps to prevent the tip of thecatheter assembly from prolapsing, a condition that could occur if tip616 ceased advancing on guidewire 430 (e.g. jammed) while continuedadvancement forces on the catheter jacket could cause location 660 and662 to approach one another and cause the working head section of thecatheter to buckle. In an alternate embodiment (not shown) the bridgingguidewire lumen 612 can be shortened, modified or even removed fromsection 662 of the working head 600, much like the embodiment of FIG. 4.To prevent catheter prolapse in this situation the distal portion of thecatheter could be strengthened with higher durometer polymers ormaterials such as Nitinol to provide a durable yet flexible design thatis resistant to buckling.

In order to assist in preparing the device for insertion into a body,there may be a benefit to providing a removable tool that would assistthe user in the loading of the catheter onto the guidewire. For example,in the instance where backloading of the guidewire into guidewirefollowing means or guidewire lumen of the catheter proves necessary, aloading tool may be provided to ensure that the guidewire is directedappropriately into the guidewire following means and guidewire lumen.The removable tool may provide, for example, a funnel to place theguidewire, and restrict the independent movement of the guidewire awayfrom the catheter until the guidewire is securely loaded into theguidewire lumen or other guidewire following means, at which point, theloading tool may be removed to allow advancing the catheter into thebody over the guidewire.

With reference to FIG. 5, there is depicted one embodiment of theworking head 500, featuring a cap 502 having at least one aspirationinlet port 504, an infusate delivery port 506, and a guidewire followingmeans 508. The guidewire following means features an opening in thedistal tip, through which a guidewire may be slidably arranged. In thismanner, the catheter assembly can follow along the guidewire as theassembly is urged further into the body, in order to arrive at thetreatment site.

In a preferred embodiment, as depicted in FIG. 4, there is provided aflexible atraumatic tip 416 at the distal end of the working head 400,the atraumatic tip being operatively attached to the cap 402 of theworking head. The atraumatic tip 416 is preferably a compliantbiocompatible material (e.g., nitinol, silicone, latex, PTFE, etc.), ora compliant material coated with a biocompatible coating to enhanceslidability, and features an opening 408 at the distal end of theatraumatic tip through which a guidewire may be slidably arranged. Inuse, the compliant atraumatic tip 416 is able to conform to the bend ofthe vessel, in order to help guide the catheter as it is urged furtherinto the patient. The flexible atraumatic tip 416 may further feature arecessed area or channel 418 in order to accommodate a portion of theguidewire, further reducing the cross-sectional area of the atraumatictip as it follows the guidewire. The design of this embodiment enhancesthe ability of the device to navigate bends in narrow vessels, withoutcausing harm to the vessel, as the distal tip of the working head 400with the flexible atraumatic tip 416 more easily navigates the bends andhelps conform the vasculature to accept the passage of the assembly.This embodiment featuring a flexible atraumatic tip 416 may also featurethe side-by-side guidewire lumen 412, as discussed above. As shown, theguidewire (not shown) would be free to flex independently of the devicefor a portion running alongside working head 400 of the device. Theindependently flexible portion of the guidewire would serve to ensurethat the guidewire is not interfering with the bend of the catheter intraversing a sharp narrow bend in the vasculature, as the guidewirewould be displaced alongside the bending of the catheter, rather thanaffixed on the outside or the inside of the bend, and further adding tothe cross-section that needs to be bent in order to comply with thevasculature.

It is recognized the device may also feature distal protection measures(not shown). For example, in the embodiment of the device using aguidewire in a monorail fashion, the guidewire may have at least onedistal protection measure (e.g., expandable balloon, umbrella filter,etc.) that serves to ensure debris or material is not released away fromthe treatment site during the course of the procedure. With the devicefollowing along the guidewire in a monorail fashion, there is no needfor the guide wire, with or without a distal protection measure, totraverse through the interior of the length of the device, and adding tothe crossing profile. The device featuring a distal end as depicted inFIG. 5 may be especially suitable for use with distal protectiondevices. The cap 502, having a relatively short length extendingdistally beyond the aspiration inlet ports 504, may serve to reduce theamount of occlusive material that may remain up against the distalprotection device.

Thus since the invention disclosed herein may be embodied in otherspecific forms without departing from the spirit or generalcharacteristics thereof, some of which forms have been indicated, theembodiments described herein are to be considered in all respectsillustrative and not restrictive, by applying current or futureknowledge. The scope of the invention is to be indicated by the appendedclaims, rather than by the foregoing description, and all changes whichcome within the meaning and range of equivalency of the claims areintended to be embraced therein.

What is claimed is:
 1. A flexible catheter system for clearing an accumulation of occlusive material from a vessel, duct or lumen in a living being, the flexible catheter system comprising: an aspiration pump, wherein the aspiration pump comprises a helical wire, a core having a proximal end, and a catheter jacket, and a cap affixed to a distal end of the catheter jacket, wherein the catheter jacket surrounds the helical wire, wherein the helical wire is wrapped around the core in a helical arrangement and affixed to the core only at the proximal end, wherein the cap comprises at least one aspiration port, wherein the helical wire is configured to create suction through the aspiration port when the helical wire is rotated inside the cap, and wherein a proximal portion of the helical wire is coupled to and driven by a helical source of rotary power to flex independently of the core and catheter jacket.
 2. The flexible catheter system of claim 1, wherein the helical wire is attached to the cap and wherein the core is arranged to rotate in the same direction of the helical wire.
 3. The flexible catheter system of claim 1, wherein the helical wire is attached to the cap and wherein the core is arranged to rotate in the opposite direction of the helical wire.
 4. The flexible catheter system of claim 3, further comprising a core source of rotary power to rotate the core, and wherein the core source of rotary power is independent of the helical source of rotary power.
 5. The flexible catheter system of claim 3, wherein the cap is generally aligned and continuous with the catheter jacket, wherein at least a portion of the flexible catheter system at a distal region is sufficiently flexible or deflectable as to allow the flexible catheter system to deflect away from a guidewire such that the catheter jacket within the flexible catheter system is separated from the guidewire by a separation distance when the helical source of rotary power is energized and rotates the helical wire in the lumen, and wherein the independent rotation of the core serves to deflect the distal tip of the flexible catheter system to improve the removal of occlusive material.
 6. The flexible catheter system of claim 1, wherein the helical wire is formed having a cutting edge at or near the distal end, wherein the helical wire does not extend uninterrupted for an entire length of the core, thereby providing increased flexibility in the regions where there is no helical wire, and wherein the core is hollow and is arranged to allow delivery of an infusate fluid from an infusate pump into the vessel, duct or lumen.
 7. The flexible catheter system of claim 6, wherein the infusate pump is arranged to operate independently of either the helical wire and the core, wherein the cap comprises at least one outlet port, the at least one outlet port being arranged to allow a flow of infusate fluid therethrough to the vessel, duct or lumen, the at least one outlet port directs the flow of the infusate fluid radially, towards a wall of the vessel, duct or lumen; or distally, into the vessel, duct or lumen; or proximally, towards an inlet port and further comprising: a safety mechanism, the safety mechanism comprising a valve means being arranged to selectively open and close to allow the infusate fluid flow to the vessel, duct or lumen in response to aspiration flow from the vessel, duct or lumen through operation of the aspiration pump.
 8. The flexible catheter system of claim 1, wherein the aspiration pump comprises a rotor within the catheter jacket and a clearance between the rotor and an inner surface of the catheter jacket is 33% or less of the rotor diameter and the rotor being arranged to allow free rotation of the rotor within the surrounding catheter jacket when flexed, the free rotation being of sufficiently high speed to overcome leakage due to the clearance and further comprising a guidewire following means.
 9. The flexible catheter system of claim 1, wherein the at least one aspiration port has a sharp cutting edge forming the periphery thereof, the at least one aspiration port being arranged to allow the passage of the occlusive material therethrough to the aspiration pump; whereby the occlusive material will be cut by the sharp cutting edge of the at least one aspiration port to form fragments of a size capable of being conveyed by the aspiration pump and further comprising a distal protection and a holding arrangement that secures a guidewire to a distal end of the flexible catheter system, wherein the holding arrangement holds the guidewire adjacent to the flexible catheter system at two spaced-apart points on either side of a segment of the flexible catheter system such that the segment may move laterally relative to the guidewire; and wherein the segment of the flexible catheter system may move in a laterally curved path towards the guidewire and away from the guidewire when the helical source of rotary power is activated such that the segment of the flexible catheter system is a farther distance from the guidewire when the helical source of rotary power is activated as compared to when the helical source of rotary power is not activated.
 10. The catheter system of claim 1, wherein the helical wire comprises a plurality of zones, and the helix has a different pitch in each of the zones.
 11. A flexible catheter system for clearing an accumulation of occlusive material from a vessel, duct or lumen in a living being, the flexible catheter system comprising a catheter comprising a catheter jacket housing a helical coil, and a core wire having a proximal end, wherein the helical coil is disposed about the core wire and affixed to the core wire only at the proximal end, wherein the catheter jacket comprises at least one aspiration port, and further comprising a source of rotary power coupled to a proximal portion of the helical coil and arranged to flex at least the helical coil, independently of the core wire.
 12. The flexible catheter system of claim 11, wherein the catheter further comprises a guidewire following means adapted to receive a guidewire.
 13. The flexible catheter system of claim 12, wherein a distal region of the catheter jacket is arranged to be displaced laterally from the guidewire while the helical coil is in operation.
 14. The flexible catheter system of claim 12, wherein the catheter further comprises a proximal region and a distal region and a housing extending therebetween, the housing comprising the catheter jacket and defining a lumen having an entrance region at the distal region and an exit region at the proximal region, and wherein the guidewire following means holds the catheter adjacent to the guidewire at least two spaced-apart points at the distal region of the catheter.
 15. The catheter system of claim 11, wherein the helical coil comprises a plurality of zones, and the helix has a different pitch in each of the zones.
 16. A flexible catheter system for clearing an accumulation of occlusive material from a vessel, duct or lumen in a living being, the flexible catheter system comprising an aspiration pump, wherein the aspiration pump comprises a helical wire, a core having a proximal end, a catheter jacket, and a cap affixed to a distal end of the catheter jacket, wherein the core has a distal end that is held by the cap such that the core remains rotationally stationary while the helical wire rotates about the core, and wherein the cap forms an enclosure that seals the aspiration pump from the outside environment except for at least one aspiration port defined by the cap, wherein the catheter jacket surrounds the helical wire and the helical wire is wrapped around the core in a helical arrangement, wherein the helical wire is affixed to the core only at the proximal end, and wherein a proximal portion of the helical wire is driven by a source of rotary power.
 17. A flexible catheter system as in claim 16, wherein the cap comprises a tip that is at the very distal end of the flexible catheter system, the tip having a tip lumen at the distal end that is separate from a guidewire lumen such that a guidewire may exit the guidewire lumen, pass alongside the cap and then pass through the tip lumen, wherein at least a portion of the flexible catheter system at a distal region is sufficiently flexible or deflectable as to allow the flexible catheter system to deflect away from the guidewire such that the catheter jacket within the flexible catheter system is separated from the guidewire by a separation distance when the source of rotary power is energized and rotates the helical wire in the lumen.
 18. The flexible catheter system of claim 16, further comprising a holding arrangement that secures a guidewire to a distal end of the flexible catheter system, wherein the holding arrangement holds the guidewire adjacent to the flexible catheter system at two spaced-apart points on either side of a segment of the flexible catheter system such that the segment may move laterally relative to the guidewire; and wherein the segment of the flexible catheter system may move in a laterally curved path towards the guidewire and away from the guidewire when the source of rotary power is activated such that the segment of the flexible catheter system is a farther distance from the guidewire when the source of rotary power is activated as compared to when the source of rotary power is not activated.
 19. The catheter system of claim 16, wherein the helical wire comprises a plurality of zones, and the helix has a different pitch in each of the zones. 